fix(engine): default FillContext.Policy to avoid null-deref in ReportProgress

FillContext.ReportProgress dereferences Policy.Comparer, so any caller
that forgot to set Policy hit a NullReferenceException. Default to
FillPolicy(DefaultFillComparer) so tests and ad-hoc callers work without
boilerplate.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -211,8 +211,5 @@ FakesAssemblies/
 .superpowers/
 docs/superpowers/
 
-# Documentation (manuals, templates, etc.)
-docs/
-
 # Launch settings
 **/Properties/launchSettings.json

CLAUDE.md

@@ -57,6 +57,8 @@ File I/O and format conversion. Uses ACadSharp for DXF/DWG support.
 - `NestReader`/`NestWriter` — custom ZIP-based nest format (JSON metadata + G-code programs, v2 format).
 - `ProgramReader` — G-code text parser.
 - `Extensions` — conversion helpers between ACadSharp and OpenNest geometry types.
+- `CadImporter` — shared "DXF → Drawing" service used by the UI, console, MCP, API, and training projects. Two-stage API: `Import(path, options)` loads raw entities, runs bend detection, and returns a mutable `CadImportResult`; `BuildDrawing(result, visible, bends, quantity, customer, editedProgram)` produces a fully-populated `Drawing` with `Source.Offset`, `SourceEntities`, `SuppressedEntityIds`, and bends. `ImportDrawing(path, options)` composes both stages for headless callers.
+- `CadImportOptions`, `CadImportResult` — inputs and intermediate state for `CadImporter`.
 
 ### OpenNest.Console (console app, depends on Core + Engine + IO)
 Command-line interface for batch nesting. Supports DXF import, plate configuration, linear fill, and NFP-based auto-nesting (`--autonest`).
@@ -117,3 +119,4 @@ Always keep `README.md` and `CLAUDE.md` up to date when making changes that affe
 - `FillScore` uses lexicographic comparison (count > utilization > compactness) to rank fill results consistently across all fill strategies.
 - **Cut-off materialization lifecycle**: `CutOff` objects live on `Plate.CutOffs`. Each generates a `Drawing` (with `IsCutOff = true`) whose `Program` contains trimmed line segments. `Plate.RegenerateCutOffs(settings)` removes old cut-off Parts, recomputes programs, and re-adds them to `Plate.Parts`. Regeneration triggers: cut-off add/remove/move, part drag complete, fill complete, plate transform. Cut-off Parts are excluded from quantity tracking, utilization, overlap detection, and nest file serialization (programs are regenerated from definitions on load).
 - **User-defined G-code variables**: Programs can contain named variable definitions (`name = expression [inline] [global]`) referenced in coordinates with `$name`. Variables resolve to doubles at parse time for geometry/nesting. `VariableRefs` on `Motion`/`Feedrate` track the symbolic link so post processors can emit machine variable references. Cincinnati post maps non-inline variables to numbered machine variables (`#200+`) with descriptive comments. Global variables share a number across programs; local variables get per-drawing numbers. `ProgramReader` uses a two-pass parse (collect definitions, then parse G-code with substitution). `NestWriter` serializes definitions and `$references` back to text for round-trip fidelity.
+- **CAD import pipeline**: All "DXF → Drawing" conversion goes through `OpenNest.IO.CadImporter`. The UI form uses `Import` on file load (storing the mutable result in a `FileListItem`) and `BuildDrawing` on save (passing the user's current visible entities and bends). Console, MCP, API, and Training projects use `ImportDrawing` for headless conversion. This guarantees all callers produce drawings with the same shape: pierce-point `Source.Offset`, stable `SourceEntities` with GUIDs, `SuppressedEntityIds`, detected bends, and metadata.

OpenNest.Api/NestRunner.cs

@@ -5,8 +5,6 @@ using System.IO;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using OpenNest.Converters;
-using OpenNest.Geometry;
 using OpenNest.IO;
 
 namespace OpenNest.Api;
@@ -30,15 +28,21 @@ public static class NestRunner
             if (!File.Exists(part.DxfPath))
                 throw new FileNotFoundException($"DXF file not found: {part.DxfPath}", part.DxfPath);
 
-            var geometry = Dxf.GetGeometry(part.DxfPath);
+            Drawing drawing;
-            if (geometry.Count == 0)
+            try
+            {
+                drawing = CadImporter.ImportDrawing(part.DxfPath,
+                    new CadImportOptions { Quantity = part.Quantity });
+            }
+            catch (System.Exception ex)
+            {
+                throw new InvalidOperationException(
+                    $"Failed to import DXF: {part.DxfPath}", ex);
+            }
+
+            if (drawing.Program == null || drawing.Program.Codes.Count == 0)
                 throw new InvalidOperationException($"Failed to import DXF: {part.DxfPath}");
 
-            var normalized = ShapeProfile.NormalizeEntities(geometry);
-            var pgm = ConvertGeometry.ToProgram(normalized);
-            var name = Path.GetFileNameWithoutExtension(part.DxfPath);
-            var drawing = new Drawing(name);
-            drawing.Program = pgm;
             drawings.Add(drawing);
         }
 

OpenNest.Console/Program.cs

@@ -1,5 +1,4 @@
 using OpenNest;
-using OpenNest.Converters;
 using OpenNest.Geometry;
 using OpenNest.IO;
 using System;
@@ -241,25 +240,15 @@ static class NestConsole
 
     static Drawing ImportDxf(string path)
     {
-        var geometry = Dxf.GetGeometry(path);
+        try
-
-        if (geometry.Count == 0)
         {
-            Console.Error.WriteLine($"Error: failed to read DXF file or no geometry found: {path}");
+            return CadImporter.ImportDrawing(path);
+        }
+        catch (System.Exception ex)
+        {
+            Console.Error.WriteLine($"Error: failed to import DXF '{path}': {ex.Message}");
             return null;
         }
-
-        var normalized = ShapeProfile.NormalizeEntities(geometry);
-        var pgm = ConvertGeometry.ToProgram(normalized);
-
-        if (pgm == null)
-        {
-            Console.Error.WriteLine($"Error: failed to convert geometry: {path}");
-            return null;
-        }
-
-        var name = Path.GetFileNameWithoutExtension(path);
-        return new Drawing(name, pgm);
     }
 
     static void ApplyTemplate(Plate plate, Options options)

OpenNest.Core/CNC/CuttingStrategy/ContourCuttingStrategy.cs

@@ -1,5 +1,6 @@
 using OpenNest.Geometry;
 using OpenNest.Math;
+using System;
 using System.Collections.Generic;
 
 namespace OpenNest.CNC.CuttingStrategy
@@ -11,6 +12,11 @@ namespace OpenNest.CNC.CuttingStrategy
         private record ContourEntry(Shape Shape, Vector Point, Entity Entity);
 
         public CuttingResult Apply(Program partProgram, Vector approachPoint)
+        {
+            return Apply(partProgram, approachPoint, Vector.Invalid);
+        }
+
+        public CuttingResult Apply(Program partProgram, Vector approachPoint, Vector nextPartStart)
         {
             var entities = partProgram.ToGeometry();
             entities.RemoveAll(e => e.Layer == SpecialLayers.Rapid);
@@ -20,14 +26,43 @@ namespace OpenNest.CNC.CuttingStrategy
 
             var profile = new ShapeProfile(entities);
 
-            // Forward pass: sequence cutouts nearest-neighbor from perimeter
+            // Start from the bounding box corner opposite the origin (max X, max Y)
-            var perimeterPoint = profile.Perimeter.ClosestPointTo(approachPoint, out _);
+            var bbox = entities.GetBoundingBox();
-            var orderedCutouts = SequenceCutouts(profile.Cutouts, perimeterPoint);
+            var startCorner = new Vector(bbox.Right, bbox.Top);
+
+            // Initial pass: sequence cutouts from bbox corner
+            var seedPoint = startCorner;
+            var orderedCutouts = SequenceCutouts(profile.Cutouts, seedPoint);
             orderedCutouts.Reverse();
 
-            // Backward pass: walk from perimeter back through cutting order
+            var perimeterSeed = profile.Perimeter.ClosestPointTo(seedPoint, out _);
-            // so each lead-in faces the next cutout to be cut, not the previous
+            var cutoutEntries = ResolveLeadInPoints(orderedCutouts, perimeterSeed);
-            var cutoutEntries = ResolveLeadInPoints(orderedCutouts, perimeterPoint);
+
+            Vector perimeterPt;
+            Entity perimeterEntity;
+
+            if (!double.IsNaN(nextPartStart.X) && cutoutEntries.Count > 0)
+            {
+                // Iterate: each pass refines the perimeter lead-in which changes
+                // the internal sequence which changes the last cutout position
+                for (var iter = 0; iter < 3; iter++)
+                {
+                    var lastCutoutPt = cutoutEntries[cutoutEntries.Count - 1].Point;
+                    perimeterSeed = FindPerimeterIntersection(profile.Perimeter, lastCutoutPt, nextPartStart, out _);
+
+                    orderedCutouts = SequenceCutouts(profile.Cutouts, perimeterSeed);
+                    orderedCutouts.Reverse();
+                    cutoutEntries = ResolveLeadInPoints(orderedCutouts, perimeterSeed);
+                }
+
+                var finalLastCutout = cutoutEntries[cutoutEntries.Count - 1].Point;
+                perimeterPt = FindPerimeterIntersection(profile.Perimeter, finalLastCutout, nextPartStart, out perimeterEntity);
+            }
+            else
+            {
+                var perimeterRef = cutoutEntries.Count > 0 ? cutoutEntries[0].Point : approachPoint;
+                perimeterPt = profile.Perimeter.ClosestPointTo(perimeterRef, out perimeterEntity);
+            }
 
             var result = new Program(Mode.Absolute);
 
@@ -36,9 +71,6 @@ namespace OpenNest.CNC.CuttingStrategy
             foreach (var entry in cutoutEntries)
                 EmitContour(result, entry.Shape, entry.Point, entry.Entity);
 
-            // Perimeter last
-            var lastRefPoint = cutoutEntries.Count > 0 ? cutoutEntries[cutoutEntries.Count - 1].Point : approachPoint;
-            var perimeterPt = profile.Perimeter.ClosestPointTo(lastRefPoint, out var perimeterEntity);
             EmitContour(result, profile.Perimeter, perimeterPt, perimeterEntity, ContourType.External);
 
             result.Mode = Mode.Incremental;
@@ -187,6 +219,40 @@ namespace OpenNest.CNC.CuttingStrategy
             return new List<ContourEntry>(entries);
         }
 
+        private static Vector FindPerimeterIntersection(Shape perimeter, Vector lastCutout, Vector nextPartStart, out Entity entity)
+        {
+            var ray = new Line(lastCutout, nextPartStart);
+
+            if (perimeter.Intersects(ray, out var pts) && pts.Count > 0)
+            {
+                // Pick the intersection closest to the last cutout
+                var best = pts[0];
+                var bestDist = best.DistanceTo(lastCutout);
+
+                for (var i = 1; i < pts.Count; i++)
+                {
+                    var dist = pts[i].DistanceTo(lastCutout);
+                    if (dist < bestDist)
+                    {
+                        best = pts[i];
+                        bestDist = dist;
+                    }
+                }
+
+                return perimeter.ClosestPointTo(best, out entity);
+            }
+
+            // Fallback: closest point on perimeter to the last cutout
+            return perimeter.ClosestPointTo(lastCutout, out entity);
+        }
+
+        private static int ComputeSubProgramKey(double radius, double normalAngle)
+        {
+            var r = System.Math.Round(radius, 6);
+            var a = System.Math.Round(normalAngle, 6);
+            return HashCode.Combine(r, a);
+        }
+
         private void EmitContour(Program program, Shape shape, Vector point, Entity entity, ContourType? forceType = null)
         {
             var contourType = forceType ?? DetectContourType(shape);
@@ -197,16 +263,62 @@ namespace OpenNest.CNC.CuttingStrategy
             var leadOut = SelectLeadOut(contourType);
 
             if (contourType == ContourType.ArcCircle && entity is Circle circle)
+            {
+                if (Parameters.RoundLeadInAngles && Parameters.LeadInAngleIncrement > 0)
+                {
+                    var increment = Angle.ToRadians(Parameters.LeadInAngleIncrement);
+                    normal = System.Math.Round(normal / increment) * increment;
+                    normal = Angle.NormalizeRad(normal);
+
+                    var outwardAngle = normal - System.Math.PI;
+                    point = new Vector(
+                        circle.Center.X + circle.Radius * System.Math.Cos(outwardAngle),
+                        circle.Center.Y + circle.Radius * System.Math.Sin(outwardAngle));
+                }
+
                 leadIn = ClampLeadInForCircle(leadIn, circle, point, normal);
 
+                // Build hole sub-program relative to (0,0)
+                var holeCenter = circle.Center;
+                var relativePoint = new Vector(point.X - holeCenter.X, point.Y - holeCenter.Y);
+                var relativeCircle = new Circle(new Vector(0, 0), circle.Radius) { Rotation = circle.Rotation };
+                var relativeShape = new Shape();
+                relativeShape.Entities.Add(relativeCircle);
+
+                var subPgm = new Program(Mode.Absolute);
+                subPgm.Codes.AddRange(leadIn.Generate(relativePoint, normal, winding));
+                var reindexed = relativeShape.ReindexAt(relativePoint, relativeCircle);
+
+                if (Parameters.TabsEnabled && Parameters.TabConfig != null)
+                    reindexed = TrimShapeForTab(reindexed, relativePoint, Parameters.TabConfig.Size);
+
+                subPgm.Codes.AddRange(ConvertShapeToMoves(reindexed, relativePoint));
+                subPgm.Codes.AddRange(leadOut.Generate(relativePoint, normal, winding));
+                subPgm.Mode = Mode.Incremental;
+
+                // Deduplicate: check if an identical sub-program already exists
+                var key = ComputeSubProgramKey(circle.Radius, normal);
+                if (!program.SubPrograms.ContainsKey(key))
+                    program.SubPrograms[key] = subPgm;
+
+                program.Codes.Add(new SubProgramCall
+                {
+                    Id = key,
+                    Program = program.SubPrograms[key],
+                    Offset = holeCenter
+                });
+
+                return;
+            }
+
             program.Codes.AddRange(leadIn.Generate(point, normal, winding));
 
-            var reindexed = shape.ReindexAt(point, entity);
+            var reindexedShape = shape.ReindexAt(point, entity);
 
             if (Parameters.TabsEnabled && Parameters.TabConfig != null)
-                reindexed = TrimShapeForTab(reindexed, point, Parameters.TabConfig.Size);
+                reindexedShape = TrimShapeForTab(reindexedShape, point, Parameters.TabConfig.Size);
 
-            program.Codes.AddRange(ConvertShapeToMoves(reindexed, point));
+            program.Codes.AddRange(ConvertShapeToMoves(reindexedShape, point));
             program.Codes.AddRange(leadOut.Generate(point, normal, winding));
         }
 
@@ -309,7 +421,12 @@ namespace OpenNest.CNC.CuttingStrategy
             if (shape.Entities.Count == 1 && shape.Entities[0] is Circle circle)
                 return circle.Rotation;
 
-            return shape.ToPolygon().RotationDirection();
+            var polygon = shape.ToPolygon();
+
+            if (polygon.Vertices.Count < 3)
+                return RotationType.CCW;
+
+            return polygon.RotationDirection();
         }
 
         private LeadIn ClampLeadInForCircle(LeadIn leadIn, Circle circle, Vector contourPoint, double normalAngle)

OpenNest.Core/CNC/CuttingStrategy/CuttingParameters.cs

@@ -23,6 +23,9 @@ namespace OpenNest.CNC.CuttingStrategy
 
         public double PierceClearance { get; set; } = 0.0625;
 
+        public bool RoundLeadInAngles { get; set; }
+        public double LeadInAngleIncrement { get; set; } = 5.0;
+
         public double AutoTabMinSize { get; set; }
         public double AutoTabMaxSize { get; set; }
 

OpenNest.Core/CNC/CuttingStrategy/LeadOuts/MicrotabLeadOut.cs

@@ -1,16 +0,0 @@
-using OpenNest.Geometry;
-using System.Collections.Generic;
-
-namespace OpenNest.CNC.CuttingStrategy
-{
-    public class MicrotabLeadOut : LeadOut
-    {
-        public double GapSize { get; set; } = 0.03;
-
-        public override List<ICode> Generate(Vector contourEndPoint, double contourNormalAngle,
-            RotationType winding = RotationType.CW)
-        {
-            return new List<ICode>();
-        }
-    }
-}

OpenNest.Core/CNC/Program.cs

@@ -12,6 +12,8 @@ namespace OpenNest.CNC
 
         public Dictionary<string, VariableDefinition> Variables { get; } = new(StringComparer.OrdinalIgnoreCase);
 
+        public Dictionary<int, Program> SubPrograms { get; } = new();
+
         private Mode mode;
 
         public Program(Mode mode = Mode.Absolute)
@@ -87,6 +89,17 @@ namespace OpenNest.CNC
                 {
                     var subpgm = (SubProgramCall)code;
 
+                    if (subpgm.Offset.X != 0 || subpgm.Offset.Y != 0)
+                    {
+                        var cos = System.Math.Cos(angle);
+                        var sin = System.Math.Sin(angle);
+                        var dx = subpgm.Offset.X - origin.X;
+                        var dy = subpgm.Offset.Y - origin.Y;
+                        subpgm.Offset = new Geometry.Vector(
+                            origin.X + dx * cos - dy * sin,
+                            origin.Y + dx * sin + dy * cos);
+                    }
+
                     if (subpgm.Program != null)
                         subpgm.Program.Rotate(angle, origin);
                 }
@@ -115,6 +128,12 @@ namespace OpenNest.CNC
             {
                 var code = Codes[i];
 
+                if (code is SubProgramCall subpgm)
+                {
+                    subpgm.Offset = new Geometry.Vector(
+                        subpgm.Offset.X + x, subpgm.Offset.Y + y);
+                }
+
                 if (code is Motion == false)
                     continue;
 
@@ -137,6 +156,12 @@ namespace OpenNest.CNC
             {
                 var code = Codes[i];
 
+                if (code is SubProgramCall subpgm)
+                {
+                    subpgm.Offset = new Geometry.Vector(
+                        subpgm.Offset.X + voffset.X, subpgm.Offset.Y + voffset.Y);
+                }
+
                 if (code is Motion == false)
                     continue;
 
@@ -275,6 +300,10 @@ namespace OpenNest.CNC
 
         private Box BoundingBox(ref Vector pos)
         {
+            // Capture the frame origin at entry. Sub-program Offsets and
+            // absolute-mode endpoints are relative to this fixed origin.
+            var frameOrigin = pos;
+
             double minX = 0.0;
             double minY = 0.0;
             double maxX = 0.0;
@@ -290,7 +319,7 @@ namespace OpenNest.CNC
                         {
                             var line = (LinearMove)code;
                             var pt = Mode == Mode.Absolute ?
-                                line.EndPoint :
+                                frameOrigin + line.EndPoint :
                                 line.EndPoint + pos;
 
                             if (pt.X > maxX)
@@ -312,7 +341,7 @@ namespace OpenNest.CNC
                         {
                             var line = (RapidMove)code;
                             var pt = Mode == Mode.Absolute
-                                ? line.EndPoint
+                                ? frameOrigin + line.EndPoint
                                 : line.EndPoint + pos;
 
                             if (pt.X > maxX)
@@ -345,8 +374,8 @@ namespace OpenNest.CNC
                             }
                             else
                             {
-                                endpt = arc.EndPoint;
+                                endpt = frameOrigin + arc.EndPoint;
-                                centerpt = arc.CenterPoint;
+                                centerpt = frameOrigin + arc.CenterPoint;
                             }
 
                             double minX1;
@@ -420,6 +449,12 @@ namespace OpenNest.CNC
                     case CodeType.SubProgramCall:
                         {
                             var subpgm = (SubProgramCall)code;
+                            if (subpgm.Program == null)
+                                break;
+
+                            // Sub-program frame origin in this program's frame
+                            // is frameOrigin + Offset, regardless of current pos.
+                            pos = frameOrigin + subpgm.Offset;
                             var box = subpgm.Program.BoundingBox(ref pos);
 
                             if (box.Left < minX)
@@ -460,6 +495,9 @@ namespace OpenNest.CNC
             foreach (var kvp in Variables)
                 pgm.Variables[kvp.Key] = kvp.Value;
 
+            foreach (var kvp in SubPrograms)
+                pgm.SubPrograms[kvp.Key] = (Program)kvp.Value.Clone();
+
             return pgm;
         }
 

OpenNest.Core/CNC/SubProgramCall.cs

@@ -1,4 +1,6 @@
-using OpenNest.Math;
+using System.Text;
+using OpenNest.Geometry;
+using OpenNest.Math;
 
 namespace OpenNest.CNC
 {
@@ -35,6 +37,12 @@ namespace OpenNest.CNC
             }
         }
 
+        /// <summary>
+        /// Gets or sets the offset (position) at which the sub-program is executed.
+        /// For hole sub-programs, this is the hole center.
+        /// </summary>
+        public Vector Offset { get; set; }
+
         /// <summary>
         /// Gets or sets the rotation of the program in degrees.
         /// </summary>
@@ -78,12 +86,18 @@ namespace OpenNest.CNC
         /// <returns></returns>
         public ICode Clone()
         {
-            return new SubProgramCall(program, Rotation);
+            return new SubProgramCall(program, Rotation) { Id = Id, Offset = Offset };
         }
 
         public override string ToString()
         {
-            return string.Format("G65 P{0} R{1}", Id, Rotation);
+            var sb = new StringBuilder();
+            sb.Append($"G65 P{Id}");
+            if (Offset.X != 0 || Offset.Y != 0)
+                sb.Append($" X{Offset.X} Y{Offset.Y}");
+            if (Rotation != 0)
+                sb.Append($" R{Rotation}");
+            return sb.ToString();
         }
     }
 }

OpenNest.Core/Converters/ConvertGeometry.cs

@@ -97,7 +97,7 @@ namespace OpenNest.Converters
             if (startpt != lastpt)
                 pgm.MoveTo(startpt);
 
-            pgm.ArcTo(startpt, circle.Center, RotationType.CCW);
+            pgm.ArcTo(startpt, circle.Center, circle.Rotation);
 
             lastpt = startpt;
             return lastpt;

OpenNest.Core/Converters/ConvertMode.cs

@@ -1,4 +1,4 @@
-using OpenNest.CNC;
+using OpenNest.CNC;
 using OpenNest.Geometry;
 
 namespace OpenNest.Converters
@@ -9,7 +9,6 @@ namespace OpenNest.Converters
         /// Converts the program to absolute coordinates.
         /// Does NOT check program mode before converting.
         /// </summary>
-        /// <param name="pgm"></param>
         public static void ToAbsolute(Program pgm)
         {
             var pos = new Vector(0, 0);
@@ -17,21 +16,27 @@ namespace OpenNest.Converters
             for (int i = 0; i < pgm.Codes.Count; ++i)
             {
                 var code = pgm.Codes[i];
-                var motion = code as Motion;
 
-                if (motion != null)
+                if (code is SubProgramCall subCall && subCall.Program != null)
                 {
-                    motion.Offset(pos);
+                    // Sub-program is placed at Offset in this program's frame.
+                    // After it runs, the tool is at Offset + (sub's end in its own frame).
+                    pos = ComputeEndPosition(subCall.Program, subCall.Offset);
+                    continue;
+                }
+
+                if (code is Motion motion)
+                {
+                    motion.Offset(pos.X, pos.Y);
                     pos = motion.EndPoint;
                 }
             }
         }
 
         /// <summary>
-        /// Converts the program to intermental coordinates.
+        /// Converts the program to incremental coordinates.
         /// Does NOT check program mode before converting.
         /// </summary>
-        /// <param name="pgm"></param>
         public static void ToIncremental(Program pgm)
         {
             var pos = new Vector(0, 0);
@@ -39,9 +44,16 @@ namespace OpenNest.Converters
             for (int i = 0; i < pgm.Codes.Count; ++i)
             {
                 var code = pgm.Codes[i];
-                var motion = code as Motion;
 
-                if (motion != null)
+                if (code is SubProgramCall subCall && subCall.Program != null)
+                {
+                    // Sub-program is placed at Offset in this program's frame,
+                    // regardless of where the tool was before the call.
+                    pos = ComputeEndPosition(subCall.Program, subCall.Offset);
+                    continue;
+                }
+
+                if (code is Motion motion)
                 {
                     var pos2 = motion.EndPoint;
                     motion.Offset(-pos.X, -pos.Y);
@@ -49,5 +61,37 @@ namespace OpenNest.Converters
                 }
             }
         }
+
+        /// <summary>
+        /// Computes the tool position after executing <paramref name="pgm"/>,
+        /// given that the program's frame origin is at <paramref name="startPos"/>
+        /// in the caller's frame. Walks nested sub-program calls recursively.
+        /// </summary>
+        private static Vector ComputeEndPosition(Program pgm, Vector startPos)
+        {
+            var pos = startPos;
+
+            for (int i = 0; i < pgm.Codes.Count; ++i)
+            {
+                var code = pgm.Codes[i];
+
+                if (code is SubProgramCall subCall && subCall.Program != null)
+                {
+                    // Nested sub's frame origin in the caller's frame is startPos + Offset.
+                    pos = ComputeEndPosition(subCall.Program, startPos + subCall.Offset);
+                    continue;
+                }
+
+                if (code is Motion motion)
+                {
+                    if (pgm.Mode == Mode.Incremental)
+                        pos = pos + motion.EndPoint;
+                    else
+                        pos = startPos + motion.EndPoint;
+                }
+            }
+
+            return pos;
+        }
     }
 }

OpenNest.Core/Converters/ConvertProgram.cs

@@ -20,6 +20,9 @@ namespace OpenNest.Converters
 
         private static void AddProgram(Program program, ref Mode mode, ref Vector curpos, ref List<Entity> geometry)
         {
+            // Capture the frame origin at entry. Sub-program Offsets are relative
+            // to this fixed origin, not to the current tool position.
+            var frameOrigin = curpos;
             mode = program.Mode;
 
             for (int i = 0; i < program.Length; ++i)
@@ -41,12 +44,15 @@ namespace OpenNest.Converters
                         break;
 
                     case CodeType.SubProgramCall:
-                        var tmpmode = mode;
                         var subpgm = (SubProgramCall)code;
-                        var geoProgram = new Shape();
+                        var savedMode = mode;
-                        AddProgram(subpgm.Program, ref mode, ref curpos, ref geoProgram.Entities);
+
-                        geometry.Add(geoProgram);
+                        // The sub-program's frame origin in this program's frame is
-                        mode = tmpmode;
+                        // frameOrigin + Offset — independent of current tool position.
+                        curpos = new Vector(frameOrigin.X + subpgm.Offset.X, frameOrigin.Y + subpgm.Offset.Y);
+
+                        AddProgram(subpgm.Program, ref mode, ref curpos, ref geometry);
+                        mode = savedMode;
                         break;
                 }
             }
@@ -106,7 +112,7 @@ namespace OpenNest.Converters
             var layer = ConvertLayer(arcMove.Layer);
 
             if (startAngle.IsEqualTo(endAngle))
-                geometry.Add(new Circle(center, radius) { Layer = layer, Color = layer.Color });
+                geometry.Add(new Circle(center, radius) { Layer = layer, Color = layer.Color, Rotation = arcMove.Rotation });
             else
                 geometry.Add(new Arc(center, radius, startAngle, endAngle, arcMove.Rotation == RotationType.CW) { Layer = layer, Color = layer.Color });
 

OpenNest.Core/Drawing.cs

@@ -2,6 +2,7 @@
 using OpenNest.CNC;
 using OpenNest.Converters;
 using OpenNest.Geometry;
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Linq;
@@ -90,6 +91,18 @@ namespace OpenNest
 
         public List<Bend> Bends { get; set; } = new List<Bend>();
 
+        /// <summary>
+        /// Complete set of source entities with stable GUIDs.
+        /// Null when the drawing was created from G-code or an older nest file.
+        /// </summary>
+        public List<Entity> SourceEntities { get; set; }
+
+        /// <summary>
+        /// IDs of entities in <see cref="SourceEntities"/> that are suppressed (hidden).
+        /// Suppressed entities are excluded from the active Program but preserved for re-enabling.
+        /// </summary>
+        public HashSet<Guid> SuppressedEntityIds { get; set; } = new HashSet<Guid>();
+
         public double Area { get; protected set; }
 
         public void UpdateArea()

OpenNest.Core/Geometry/Entity.cs

@@ -1,4 +1,5 @@
 using OpenNest.Math;
+using System;
 using System.Collections.Generic;
 using System.Drawing;
 
@@ -10,10 +11,16 @@ namespace OpenNest.Geometry
 
         protected Entity()
         {
+            Id = Guid.NewGuid();
             Layer = OpenNest.Geometry.Layer.Default;
             boundingBox = new Box();
         }
 
+        /// <summary>
+        /// Unique identifier for this entity, stable across edit sessions.
+        /// </summary>
+        public Guid Id { get; set; }
+
         /// <summary>
         /// Entity color (resolved from DXF ByLayer/ByBlock to actual color).
         /// </summary>

OpenNest.Core/Geometry/Shape.cs

@@ -605,7 +605,7 @@ namespace OpenNest.Geometry
                         copy.Entities.Add(new Arc(a.Center, a.Radius, a.EndAngle, a.StartAngle, !a.IsReversed) { Layer = a.Layer });
                         break;
                     case Circle c:
-                        copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer });
+                        copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer, Rotation = RotationType.CW });
                         break;
                 }
             }
@@ -640,7 +640,7 @@ namespace OpenNest.Geometry
                         copy.Entities.Add(new Arc(a.Center, a.Radius, a.EndAngle, a.StartAngle, !a.IsReversed) { Layer = a.Layer });
                         break;
                     case Circle c:
-                        copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer });
+                        copy.Entities.Add(new Circle(c.Center, c.Radius) { Layer = c.Layer, Rotation = RotationType.CCW });
                         break;
                 }
             }

OpenNest.Core/Geometry/SpatialQuery.cs

@@ -104,6 +104,39 @@ namespace OpenNest.Geometry
             return double.MaxValue;
         }
 
+        /// <summary>
+        /// Solves ray-circle intersection, returning the two parametric t values.
+        /// Returns false if no real intersection exists.
+        /// </summary>
+        [System.Runtime.CompilerServices.MethodImpl(
+            System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
+        private static bool SolveRayCircle(
+            double vx, double vy,
+            double cx, double cy, double r,
+            double dirX, double dirY,
+            out double t1, out double t2)
+        {
+            var ox = vx - cx;
+            var oy = vy - cy;
+
+            var a = dirX * dirX + dirY * dirY;
+            var b = 2.0 * (ox * dirX + oy * dirY);
+            var c = ox * ox + oy * oy - r * r;
+
+            var discriminant = b * b - 4.0 * a * c;
+            if (discriminant < 0)
+            {
+                t1 = t2 = double.MaxValue;
+                return false;
+            }
+
+            var sqrtD = System.Math.Sqrt(discriminant);
+            var inv2a = 1.0 / (2.0 * a);
+            t1 = (-b - sqrtD) * inv2a;
+            t2 = (-b + sqrtD) * inv2a;
+            return true;
+        }
+
         /// <summary>
         /// Computes the distance from a point along a direction to an arc.
         /// Solves ray-circle intersection, then constrains hits to the arc's
@@ -117,25 +150,9 @@ namespace OpenNest.Geometry
             double startAngle, double endAngle, bool reversed,
             double dirX, double dirY)
         {
-            // Ray: P = (vx,vy) + t*(dirX,dirY)
+            if (!SolveRayCircle(vx, vy, cx, cy, r, dirX, dirY, out var t1, out var t2))
-            // Circle: (x-cx)^2 + (y-cy)^2 = r^2
-            var ox = vx - cx;
-            var oy = vy - cy;
-
-            // a = dirX^2 + dirY^2 = 1 for unit direction, but handle general case
-            var a = dirX * dirX + dirY * dirY;
-            var b = 2.0 * (ox * dirX + oy * dirY);
-            var c = ox * ox + oy * oy - r * r;
-
-            var discriminant = b * b - 4.0 * a * c;
-            if (discriminant < 0)
                 return double.MaxValue;
 
-            var sqrtD = System.Math.Sqrt(discriminant);
-            var inv2a = 1.0 / (2.0 * a);
-            var t1 = (-b - sqrtD) * inv2a;
-            var t2 = (-b + sqrtD) * inv2a;
-
             var best = double.MaxValue;
 
             if (t1 > -Tolerance.Epsilon)
@@ -168,27 +185,13 @@ namespace OpenNest.Geometry
             double cx, double cy, double r,
             double dirX, double dirY)
         {
-            var ox = vx - cx;
+            if (!SolveRayCircle(vx, vy, cx, cy, r, dirX, dirY, out var t1, out var t2))
-            var oy = vy - cy;
-
-            var a = dirX * dirX + dirY * dirY;
-            var b = 2.0 * (ox * dirX + oy * dirY);
-            var c = ox * ox + oy * oy - r * r;
-
-            var discriminant = b * b - 4.0 * a * c;
-            if (discriminant < 0)
                 return double.MaxValue;
 
-            var sqrtD = System.Math.Sqrt(discriminant);
+            if (t1 > Tolerance.Epsilon) return t1;
-            var t = (-b - sqrtD) / (2.0 * a);
+            if (t1 >= -Tolerance.Epsilon) return 0;
-
+            if (t2 > Tolerance.Epsilon) return t2;
-            if (t > Tolerance.Epsilon) return t;
+            if (t2 >= -Tolerance.Epsilon) return 0;
-            if (t >= -Tolerance.Epsilon) return 0;
-
-            // First root is behind us, try the second
-            t = (-b + sqrtD) / (2.0 * a);
-            if (t > Tolerance.Epsilon) return t;
-            if (t >= -Tolerance.Epsilon) return 0;
 
             return double.MaxValue;
         }
@@ -200,57 +203,7 @@ namespace OpenNest.Geometry
         /// </summary>
         public static double DirectionalDistance(List<Line> movingLines, List<Line> stationaryLines, PushDirection direction)
         {
-            var minDist = double.MaxValue;
+            return DirectionalDistance(movingLines, 0, 0, stationaryLines, direction);
-
-            // Case 1: Each moving vertex -> each stationary edge
-            var movingVertices = new HashSet<Vector>();
-            for (int i = 0; i < movingLines.Count; i++)
-            {
-                movingVertices.Add(movingLines[i].pt1);
-                movingVertices.Add(movingLines[i].pt2);
-            }
-
-            var stationaryEdges = new (Vector start, Vector end)[stationaryLines.Count];
-            for (int i = 0; i < stationaryLines.Count; i++)
-                stationaryEdges[i] = (stationaryLines[i].pt1, stationaryLines[i].pt2);
-
-            // Sort edges for pruning if not already sorted (usually they aren't here)
-            if (direction == PushDirection.Left || direction == PushDirection.Right)
-                stationaryEdges = stationaryEdges.OrderBy(e => System.Math.Min(e.start.Y, e.end.Y)).ToArray();
-            else
-                stationaryEdges = stationaryEdges.OrderBy(e => System.Math.Min(e.start.X, e.end.X)).ToArray();
-
-            foreach (var mv in movingVertices)
-            {
-                var d = OneWayDistance(mv, stationaryEdges, Vector.Zero, direction);
-                if (d < minDist) minDist = d;
-            }
-
-            // Case 2: Each stationary vertex -> each moving edge (opposite direction)
-            var opposite = OppositeDirection(direction);
-            var stationaryVertices = new HashSet<Vector>();
-            for (int i = 0; i < stationaryLines.Count; i++)
-            {
-                stationaryVertices.Add(stationaryLines[i].pt1);
-                stationaryVertices.Add(stationaryLines[i].pt2);
-            }
-
-            var movingEdges = new (Vector start, Vector end)[movingLines.Count];
-            for (int i = 0; i < movingLines.Count; i++)
-                movingEdges[i] = (movingLines[i].pt1, movingLines[i].pt2);
-
-            if (opposite == PushDirection.Left || opposite == PushDirection.Right)
-                movingEdges = movingEdges.OrderBy(e => System.Math.Min(e.start.Y, e.end.Y)).ToArray();
-            else
-                movingEdges = movingEdges.OrderBy(e => System.Math.Min(e.start.X, e.end.X)).ToArray();
-
-            foreach (var sv in stationaryVertices)
-            {
-                var d = OneWayDistance(sv, movingEdges, Vector.Zero, opposite);
-                if (d < minDist) minDist = d;
-            }
-
-            return minDist;
         }
 
         /// <summary>
@@ -265,21 +218,10 @@ namespace OpenNest.Geometry
             var movingOffset = new Vector(movingDx, movingDy);
 
             // Case 1: Each moving vertex -> each stationary edge
-            var movingVertices = new HashSet<Vector>();
+            var movingVertices = CollectVertices(movingLines, movingOffset);
-            for (int i = 0; i < movingLines.Count; i++)
-            {
-                movingVertices.Add(movingLines[i].pt1 + movingOffset);
-                movingVertices.Add(movingLines[i].pt2 + movingOffset);
-            }
 
-            var stationaryEdges = new (Vector start, Vector end)[stationaryLines.Count];
+            var stationaryEdges = ToEdgeArray(stationaryLines);
-            for (int i = 0; i < stationaryLines.Count; i++)
+            SortEdgesForPruning(stationaryEdges, direction);
-                stationaryEdges[i] = (stationaryLines[i].pt1, stationaryLines[i].pt2);
-
-            if (direction == PushDirection.Left || direction == PushDirection.Right)
-                stationaryEdges = stationaryEdges.OrderBy(e => System.Math.Min(e.start.Y, e.end.Y)).ToArray();
-            else
-                stationaryEdges = stationaryEdges.OrderBy(e => System.Math.Min(e.start.X, e.end.X)).ToArray();
 
             foreach (var mv in movingVertices)
             {
@@ -289,21 +231,10 @@ namespace OpenNest.Geometry
 
             // Case 2: Each stationary vertex -> each moving edge (opposite direction)
             var opposite = OppositeDirection(direction);
-            var stationaryVertices = new HashSet<Vector>();
+            var stationaryVertices = CollectVertices(stationaryLines, Vector.Zero);
-            for (int i = 0; i < stationaryLines.Count; i++)
-            {
-                stationaryVertices.Add(stationaryLines[i].pt1);
-                stationaryVertices.Add(stationaryLines[i].pt2);
-            }
 
-            var movingEdges = new (Vector start, Vector end)[movingLines.Count];
+            var movingEdges = ToEdgeArray(movingLines);
-            for (int i = 0; i < movingLines.Count; i++)
+            SortEdgesForPruning(movingEdges, opposite);
-                movingEdges[i] = (movingLines[i].pt1, movingLines[i].pt2);
-
-            if (opposite == PushDirection.Left || opposite == PushDirection.Right)
-                movingEdges = movingEdges.OrderBy(e => System.Math.Min(e.start.Y, e.end.Y)).ToArray();
-            else
-                movingEdges = movingEdges.OrderBy(e => System.Math.Min(e.start.X, e.end.X)).ToArray();
 
             foreach (var sv in stationaryVertices)
             {
@@ -342,15 +273,11 @@ namespace OpenNest.Geometry
         {
             var minDist = double.MaxValue;
 
-            // Extract unique vertices from moving edges.
+            SortEdgesForPruning(stationaryEdges, direction);
-            var movingVertices = new HashSet<Vector>();
-            for (var i = 0; i < movingEdges.Length; i++)
-            {
-                movingVertices.Add(movingEdges[i].start + movingOffset);
-                movingVertices.Add(movingEdges[i].end + movingOffset);
-            }
 
             // Case 1: Each moving vertex -> each stationary edge
+            var movingVertices = CollectVertices(movingEdges, movingOffset);
+
             foreach (var mv in movingVertices)
             {
                 var d = OneWayDistance(mv, stationaryEdges, stationaryOffset, direction);
@@ -359,12 +286,9 @@ namespace OpenNest.Geometry
 
             // Case 2: Each stationary vertex -> each moving edge (opposite direction)
             var opposite = OppositeDirection(direction);
-            var stationaryVertices = new HashSet<Vector>();
+            SortEdgesForPruning(movingEdges, opposite);
-            for (var i = 0; i < stationaryEdges.Length; i++)
+
-            {
+            var stationaryVertices = CollectVertices(stationaryEdges, stationaryOffset);
-                stationaryVertices.Add(stationaryEdges[i].start + stationaryOffset);
-                stationaryVertices.Add(stationaryEdges[i].end + stationaryOffset);
-            }
 
             foreach (var sv in stationaryVertices)
             {
@@ -556,12 +480,7 @@ namespace OpenNest.Geometry
             var dirX = direction.X;
             var dirY = direction.Y;
 
-            var movingVertices = new HashSet<Vector>();
+            var movingVertices = CollectVertices(movingLines, Vector.Zero);
-            for (var i = 0; i < movingLines.Count; i++)
-            {
-                movingVertices.Add(movingLines[i].pt1);
-                movingVertices.Add(movingLines[i].pt2);
-            }
 
             foreach (var mv in movingVertices)
             {
@@ -576,12 +495,7 @@ namespace OpenNest.Geometry
             var oppX = -dirX;
             var oppY = -dirY;
 
-            var stationaryVertices = new HashSet<Vector>();
+            var stationaryVertices = CollectVertices(stationaryLines, Vector.Zero);
-            for (var i = 0; i < stationaryLines.Count; i++)
-            {
-                stationaryVertices.Add(stationaryLines[i].pt1);
-                stationaryVertices.Add(stationaryLines[i].pt2);
-            }
 
             foreach (var sv in stationaryVertices)
             {
@@ -596,6 +510,284 @@ namespace OpenNest.Geometry
             return minDist;
         }
 
+        /// <summary>
+        /// Computes the minimum translation distance along a push direction
+        /// before any vertex/edge of movingEntities contacts any vertex/edge of
+        /// stationaryEntities. Delegates to the Vector-based overload.
+        /// </summary>
+        public static double DirectionalDistance(
+            List<Entity> movingEntities, List<Entity> stationaryEntities, PushDirection direction)
+        {
+            return DirectionalDistance(movingEntities, stationaryEntities, DirectionToOffset(direction, 1.0));
+        }
+
+        /// <summary>
+        /// Computes the minimum translation distance along an arbitrary unit direction
+        /// before any vertex/edge of movingEntities contacts any vertex/edge of
+        /// stationaryEntities. Works with native Line, Arc, and Circle entities
+        /// without tessellation.
+        /// </summary>
+        public static double DirectionalDistance(
+            List<Entity> movingEntities, List<Entity> stationaryEntities, Vector direction)
+        {
+            var minDist = double.MaxValue;
+            var dirX = direction.X;
+            var dirY = direction.Y;
+
+            var movingVertices = ExtractEntityVertices(movingEntities);
+
+            for (var v = 0; v < movingVertices.Length; v++)
+            {
+                var vx = movingVertices[v].X;
+                var vy = movingVertices[v].Y;
+
+                for (var j = 0; j < stationaryEntities.Count; j++)
+                {
+                    var d = RayEntityDistance(vx, vy, stationaryEntities[j], dirX, dirY);
+                    if (d < minDist)
+                    {
+                        minDist = d;
+                        if (d <= 0) return 0;
+                    }
+                }
+            }
+
+            var oppX = -dirX;
+            var oppY = -dirY;
+
+            var stationaryVertices = ExtractEntityVertices(stationaryEntities);
+
+            for (var v = 0; v < stationaryVertices.Length; v++)
+            {
+                var vx = stationaryVertices[v].X;
+                var vy = stationaryVertices[v].Y;
+
+                for (var j = 0; j < movingEntities.Count; j++)
+                {
+                    var d = RayEntityDistance(vx, vy, movingEntities[j], oppX, oppY);
+                    if (d < minDist)
+                    {
+                        minDist = d;
+                        if (d <= 0) return 0;
+                    }
+                }
+            }
+
+            // Phase 3: Arc-to-line closest-point check.
+            // Phases 1-2 sample arc endpoints and cardinal extremes, but the actual
+            // closest point on a small corner arc to a straight edge may lie between
+            // those samples. Use ClosestPointTo to find it and fire a ray from there.
+            minDist = ArcToLineClosestDistance(movingEntities, stationaryEntities, dirX, dirY, minDist);
+            if (minDist <= 0) return 0;
+            minDist = ArcToLineClosestDistance(stationaryEntities, movingEntities, oppX, oppY, minDist);
+            if (minDist <= 0) return 0;
+
+            // Phase 4: Curve-to-curve direct distance.
+            // The vertex-to-entity approach misses the closest contact between two
+            // curved entities (circles/arcs) because only a few cardinal vertices are
+            // sampled. The true closest contact along the push direction is found by
+            // treating it as a ray from one center to an expanded circle at the other
+            // center (radius = r1 + r2).
+            for (var i = 0; i < movingEntities.Count; i++)
+            {
+                var me = movingEntities[i];
+                if (!TryGetCurveParams(me, out var mcx, out var mcy, out var mr))
+                    continue;
+
+                for (var j = 0; j < stationaryEntities.Count; j++)
+                {
+                    var se = stationaryEntities[j];
+                    if (!TryGetCurveParams(se, out var scx, out var scy, out var sr))
+                        continue;
+
+                    var d = RayCircleDistance(mcx, mcy, scx, scy, mr + sr, dirX, dirY);
+
+                    if (d >= minDist)
+                        continue;
+
+                    // For arcs, verify the contact point falls within both arcs' angular ranges.
+                    if (me is Arc || se is Arc)
+                    {
+                        var mx = mcx + d * dirX;
+                        var my = mcy + d * dirY;
+                        var toCx = scx - mx;
+                        var toCy = scy - my;
+
+                        if (me is Arc mArc)
+                        {
+                            var angle = Angle.NormalizeRad(System.Math.Atan2(toCy, toCx));
+                            if (!Angle.IsBetweenRad(angle, mArc.StartAngle, mArc.EndAngle, mArc.IsReversed))
+                                continue;
+                        }
+
+                        if (se is Arc sArc)
+                        {
+                            var angle = Angle.NormalizeRad(System.Math.Atan2(-toCy, -toCx));
+                            if (!Angle.IsBetweenRad(angle, sArc.StartAngle, sArc.EndAngle, sArc.IsReversed))
+                                continue;
+                        }
+                    }
+
+                    minDist = d;
+                    if (d <= 0) return 0;
+                }
+            }
+
+            return minDist;
+        }
+
+        private static double ArcToLineClosestDistance(
+            List<Entity> arcEntities, List<Entity> lineEntities,
+            double dirX, double dirY, double minDist)
+        {
+            for (var i = 0; i < arcEntities.Count; i++)
+            {
+                if (arcEntities[i] is Arc arc)
+                {
+                    for (var j = 0; j < lineEntities.Count; j++)
+                    {
+                        if (lineEntities[j] is Line line)
+                        {
+                            var linePt = line.ClosestPointTo(arc.Center);
+                            var arcPt = arc.ClosestPointTo(linePt);
+                            var d = RayEdgeDistance(arcPt.X, arcPt.Y,
+                                line.pt1.X, line.pt1.Y, line.pt2.X, line.pt2.Y,
+                                dirX, dirY);
+                            if (d < minDist) { minDist = d; if (d <= 0) return 0; }
+                        }
+                    }
+                }
+            }
+            return minDist;
+        }
+
+        private static double RayEntityDistance(
+            double vx, double vy, Entity entity, double dirX, double dirY)
+        {
+            if (entity is Line line)
+            {
+                return RayEdgeDistance(vx, vy,
+                    line.pt1.X, line.pt1.Y, line.pt2.X, line.pt2.Y,
+                    dirX, dirY);
+            }
+
+            if (entity is Arc arc)
+            {
+                return RayArcDistance(vx, vy,
+                    arc.Center.X, arc.Center.Y, arc.Radius,
+                    arc.StartAngle, arc.EndAngle, arc.IsReversed,
+                    dirX, dirY);
+            }
+
+            if (entity is Circle circle)
+            {
+                return RayCircleDistance(vx, vy,
+                    circle.Center.X, circle.Center.Y, circle.Radius,
+                    dirX, dirY);
+            }
+
+            return double.MaxValue;
+        }
+
+        private static Vector[] ExtractEntityVertices(List<Entity> entities)
+        {
+            var vertices = new HashSet<Vector>();
+
+            for (var i = 0; i < entities.Count; i++)
+            {
+                var entity = entities[i];
+
+                if (entity is Line line)
+                {
+                    vertices.Add(line.pt1);
+                    vertices.Add(line.pt2);
+                }
+                else if (entity is Arc arc)
+                {
+                    vertices.Add(arc.StartPoint());
+                    vertices.Add(arc.EndPoint());
+                    AddArcExtremeVertices(vertices, arc);
+                }
+                else if (entity is Circle circle)
+                {
+                    vertices.Add(new Vector(circle.Center.X + circle.Radius, circle.Center.Y));
+                    vertices.Add(new Vector(circle.Center.X - circle.Radius, circle.Center.Y));
+                    vertices.Add(new Vector(circle.Center.X, circle.Center.Y + circle.Radius));
+                    vertices.Add(new Vector(circle.Center.X, circle.Center.Y - circle.Radius));
+                }
+            }
+
+            return vertices.ToArray();
+        }
+
+        private static void AddArcExtremeVertices(HashSet<Vector> points, Arc arc)
+        {
+            var a1 = arc.StartAngle;
+            var a2 = arc.EndAngle;
+
+            if (arc.IsReversed)
+                Generic.Swap(ref a1, ref a2);
+
+            if (Angle.IsBetweenRad(Angle.TwoPI, a1, a2))
+                points.Add(new Vector(arc.Center.X + arc.Radius, arc.Center.Y));
+            if (Angle.IsBetweenRad(Angle.HalfPI, a1, a2))
+                points.Add(new Vector(arc.Center.X, arc.Center.Y + arc.Radius));
+            if (Angle.IsBetweenRad(System.Math.PI, a1, a2))
+                points.Add(new Vector(arc.Center.X - arc.Radius, arc.Center.Y));
+            if (Angle.IsBetweenRad(System.Math.PI * 1.5, a1, a2))
+                points.Add(new Vector(arc.Center.X, arc.Center.Y - arc.Radius));
+        }
+
+        private static HashSet<Vector> CollectVertices(List<Line> lines, Vector offset)
+        {
+            return CollectVertices(ToEdgeArray(lines), offset);
+        }
+
+        private static HashSet<Vector> CollectVertices((Vector start, Vector end)[] edges, Vector offset)
+        {
+            var vertices = new HashSet<Vector>();
+            for (var i = 0; i < edges.Length; i++)
+            {
+                vertices.Add(edges[i].start + offset);
+                vertices.Add(edges[i].end + offset);
+            }
+            return vertices;
+        }
+
+        private static (Vector start, Vector end)[] ToEdgeArray(List<Line> lines)
+        {
+            var edges = new (Vector start, Vector end)[lines.Count];
+            for (var i = 0; i < lines.Count; i++)
+                edges[i] = (lines[i].pt1, lines[i].pt2);
+            return edges;
+        }
+
+        private static void SortEdgesForPruning((Vector start, Vector end)[] edges, PushDirection direction)
+        {
+            if (direction == PushDirection.Left || direction == PushDirection.Right)
+                System.Array.Sort(edges, (a, b) =>
+                    System.Math.Min(a.start.Y, a.end.Y).CompareTo(System.Math.Min(b.start.Y, b.end.Y)));
+            else
+                System.Array.Sort(edges, (a, b) =>
+                    System.Math.Min(a.start.X, a.end.X).CompareTo(System.Math.Min(b.start.X, b.end.X)));
+        }
+
+        private static bool TryGetCurveParams(Entity entity, out double cx, out double cy, out double r)
+        {
+            if (entity is Circle circle)
+            {
+                cx = circle.Center.X; cy = circle.Center.Y; r = circle.Radius;
+                return true;
+            }
+            if (entity is Arc arc)
+            {
+                cx = arc.Center.X; cy = arc.Center.Y; r = arc.Radius;
+                return true;
+            }
+            cx = cy = r = 0;
+            return false;
+        }
+
         private static double BoxProjectionMin(Box box, double dx, double dy)
         {
             var x = dx >= 0 ? box.Left : box.Right;

OpenNest.Core/IMaterialProvidingPostProcessor.cs

@@ -0,0 +1,9 @@
+using System.Collections.Generic;
+
+namespace OpenNest
+{
+    public interface IMaterialProvidingPostProcessor
+    {
+        IEnumerable<string> GetMaterialNames();
+    }
+}

OpenNest.Core/IPostProcessorNestAware.cs

@@ -0,0 +1,7 @@
+namespace OpenNest
+{
+    public interface IPostProcessorNestAware
+    {
+        void PrepareForNest(Nest nest);
+    }
+}

OpenNest.Core/Part.cs

@@ -62,10 +62,15 @@ namespace OpenNest
         public CNC.CuttingStrategy.CuttingParameters CuttingParameters { get; set; }
 
         public void ApplyLeadIns(CNC.CuttingStrategy.CuttingParameters parameters, Vector approachPoint)
+        {
+            ApplyLeadIns(parameters, approachPoint, Geometry.Vector.Invalid);
+        }
+
+        public void ApplyLeadIns(CNC.CuttingStrategy.CuttingParameters parameters, Vector approachPoint, Vector nextPartStart)
         {
             preLeadInRotation = Rotation;
             var strategy = new CNC.CuttingStrategy.ContourCuttingStrategy { Parameters = parameters };
-            var result = strategy.Apply(Program, approachPoint);
+            var result = strategy.Apply(Program, approachPoint, nextPartStart);
             Program = result.Program;
             CuttingParameters = parameters;
             HasManualLeadIns = true;
@@ -190,7 +195,14 @@ namespace OpenNest
         {
             var rotation = Rotation;
             Program = BaseDrawing.Program.Clone() as Program;
-            Program.Rotate(Program.Rotation - rotation);
+
+            if (!Math.Tolerance.IsEqualTo(rotation, 0))
+                Program.Rotate(rotation);
+
+            HasManualLeadIns = false;
+            LeadInsLocked = false;
+            CuttingParameters = null;
+            UpdateBounds();
         }
 
         /// <summary>

OpenNest.Core/PartGeometry.cs

@@ -61,6 +61,91 @@ namespace OpenNest
             return offsetShape.Entities;
         }
 
+        /// <summary>
+        /// Returns all entities (perimeter + cutouts) with spacing offset applied,
+        /// without tessellation. Perimeter is offset outward, cutouts inward.
+        /// </summary>
+        public static List<Entity> GetOffsetPartEntities(Part part, double spacing)
+        {
+            var geoEntities = ConvertProgram.ToGeometry(part.Program);
+            var profile = new ShapeProfile(
+                geoEntities.Where(e => e.Layer != SpecialLayers.Rapid).ToList());
+            var entities = new List<Entity>();
+
+            var perimeter = profile.Perimeter.OffsetOutward(spacing);
+            if (perimeter != null)
+            {
+                foreach (var entity in perimeter.Entities)
+                    entity.Offset(part.Location);
+                entities.AddRange(perimeter.Entities);
+            }
+
+            foreach (var cutout in profile.Cutouts)
+            {
+                var inset = cutout.OffsetInward(spacing);
+                if (inset == null) continue;
+                foreach (var entity in inset.Entities)
+                    entity.Offset(part.Location);
+                entities.AddRange(inset.Entities);
+            }
+
+            return entities;
+        }
+
+        /// <summary>
+        /// Returns perimeter entities at the part's world location, without tessellation
+        /// or spacing offset.
+        /// </summary>
+        public static List<Entity> GetPerimeterEntities(Part part)
+        {
+            var geoEntities = ConvertProgram.ToGeometry(part.Program);
+            var profile = new ShapeProfile(
+                geoEntities.Where(e => e.Layer != SpecialLayers.Rapid).ToList());
+
+            return CopyEntitiesAtLocation(profile.Perimeter.Entities, part.Location);
+        }
+
+        /// <summary>
+        /// Returns all entities (perimeter + cutouts) at the part's world location,
+        /// without tessellation or spacing offset.
+        /// </summary>
+        public static List<Entity> GetPartEntities(Part part)
+        {
+            var geoEntities = ConvertProgram.ToGeometry(part.Program);
+            var profile = new ShapeProfile(
+                geoEntities.Where(e => e.Layer != SpecialLayers.Rapid).ToList());
+            var entities = CopyEntitiesAtLocation(profile.Perimeter.Entities, part.Location);
+
+            foreach (var cutout in profile.Cutouts)
+                entities.AddRange(CopyEntitiesAtLocation(cutout.Entities, part.Location));
+
+            return entities;
+        }
+
+        private static List<Entity> CopyEntitiesAtLocation(List<Entity> source, Vector location)
+        {
+            var result = new List<Entity>(source.Count);
+
+            for (var i = 0; i < source.Count; i++)
+            {
+                var entity = source[i];
+                Entity copy;
+
+                if (entity is Line line)
+                    copy = new Line(line.StartPoint + location, line.EndPoint + location);
+                else if (entity is Arc arc)
+                    copy = new Arc(arc.Center + location, arc.Radius, arc.StartAngle, arc.EndAngle, arc.IsReversed);
+                else if (entity is Circle circle)
+                    copy = new Circle(circle.Center + location, circle.Radius);
+                else
+                    continue;
+
+                result.Add(copy);
+            }
+
+            return result;
+        }
+
         public static List<Line> GetOffsetPartLines(Part part, double spacing, double chordTolerance = 0.001,
             bool perimeterOnly = false)
         {

OpenNest.Core/Shapes/CircleShape.cs

@@ -7,6 +7,11 @@ namespace OpenNest.Shapes
     {
         public double Diameter { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Diameter = 8;
+        }
+
         public override Drawing GetDrawing()
         {
             var entities = new List<Entity>

OpenNest.Core/Shapes/FlangeShape.cs

@@ -11,6 +11,15 @@ namespace OpenNest.Shapes
         public double HolePatternDiameter { get; set; }
         public int HoleCount { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            NominalPipeSize = 2;
+            OD = 7.5;
+            HoleDiameter = 0.875;
+            HolePatternDiameter = 5.5;
+            HoleCount = 8;
+        }
+
         public override Drawing GetDrawing()
         {
             var entities = new List<Entity>();

OpenNest.Core/Shapes/IsoscelesTriangleShape.cs

@@ -8,6 +8,12 @@ namespace OpenNest.Shapes
         public double Base { get; set; }
         public double Height { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Base = 8;
+            Height = 10;
+        }
+
         public override Drawing GetDrawing()
         {
             var midX = Base / 2.0;

OpenNest.Core/Shapes/LShape.cs

@@ -10,6 +10,14 @@ namespace OpenNest.Shapes
         public double LegWidth { get; set; }
         public double LegHeight { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Width = 8;
+            Height = 10;
+            LegWidth = 3;
+            LegHeight = 3;
+        }
+
         public override Drawing GetDrawing()
         {
             var lw = LegWidth > 0 ? LegWidth : Width / 2.0;

OpenNest.Core/Shapes/OctagonShape.cs

@@ -7,6 +7,11 @@ namespace OpenNest.Shapes
     {
         public double Width { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Width = 8;
+        }
+
         public override Drawing GetDrawing()
         {
             var center = Width / 2.0;

OpenNest.Core/Shapes/RectangleShape.cs

@@ -8,6 +8,12 @@ namespace OpenNest.Shapes
         public double Length { get; set; }
         public double Width { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Length = 12;
+            Width = 6;
+        }
+
         public override Drawing GetDrawing()
         {
             var entities = new List<Entity>

OpenNest.Core/Shapes/RightTriangleShape.cs

@@ -8,6 +8,12 @@ namespace OpenNest.Shapes
         public double Width { get; set; }
         public double Height { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Width = 8;
+            Height = 6;
+        }
+
         public override Drawing GetDrawing()
         {
             var entities = new List<Entity>

OpenNest.Core/Shapes/RingShape.cs

@@ -8,6 +8,12 @@ namespace OpenNest.Shapes
         public double OuterDiameter { get; set; }
         public double InnerDiameter { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            OuterDiameter = 10;
+            InnerDiameter = 6;
+        }
+
         public override Drawing GetDrawing()
         {
             var entities = new List<Entity>

OpenNest.Core/Shapes/RoundedRectangleShape.cs

@@ -10,6 +10,13 @@ namespace OpenNest.Shapes
         public double Width { get; set; }
         public double Radius { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Length = 12;
+            Width = 6;
+            Radius = 1;
+        }
+
         public override Drawing GetDrawing()
         {
             var r = Radius;

OpenNest.Core/Shapes/ShapeDefinition.cs

@@ -26,6 +26,8 @@ namespace OpenNest.Shapes
 
         public abstract Drawing GetDrawing();
 
+        public virtual void SetPreviewDefaults() { }
+
         public static List<T> LoadFromJson<T>(string path) where T : ShapeDefinition
         {
             var json = File.ReadAllText(path);

OpenNest.Core/Shapes/TShape.cs

@@ -10,6 +10,14 @@ namespace OpenNest.Shapes
         public double StemWidth { get; set; }
         public double BarHeight { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            Width = 10;
+            Height = 8;
+            StemWidth = 3;
+            BarHeight = 3;
+        }
+
         public override Drawing GetDrawing()
         {
             var sw = StemWidth > 0 ? StemWidth : Width / 3.0;

OpenNest.Core/Shapes/TrapezoidShape.cs

@@ -9,6 +9,13 @@ namespace OpenNest.Shapes
         public double BottomWidth { get; set; }
         public double Height { get; set; }
 
+        public override void SetPreviewDefaults()
+        {
+            TopWidth = 6;
+            BottomWidth = 10;
+            Height = 6;
+        }
+
         public override Drawing GetDrawing()
         {
             var offset = (BottomWidth - TopWidth) / 2.0;

OpenNest.Engine/BestFit/BestFitFilter.cs

@@ -17,7 +17,8 @@ namespace OpenNest.Engine.BestFit
                 if (!result.Keep)
                     continue;
 
-                if (result.ShortestSide > System.Math.Min(MaxPlateWidth, MaxPlateHeight))
+                if (result.ShortestSide > System.Math.Min(MaxPlateWidth, MaxPlateHeight) ||
+                    result.LongestSide > System.Math.Max(MaxPlateWidth, MaxPlateHeight))
                 {
                     result.Keep = false;
                     result.Reason = "Exceeds plate dimensions";

OpenNest.Engine/BestFit/CpuDistanceComputer.cs

@@ -104,6 +104,9 @@ namespace OpenNest.Engine.BestFit
             var allMovingVerts = ExtractVerticesFromEntities(movingEntities);
             var allStationaryVerts = ExtractVerticesFromEntities(stationaryEntities);
 
+            var movingCurves = ExtractCurveParams(movingEntities);
+            var stationaryCurves = ExtractCurveParams(stationaryEntities);
+
             var vertexCache = new Dictionary<(double, double), (Vector[] leading, Vector[] facing)>();
 
             foreach (var offset in offsets)
@@ -165,12 +168,84 @@ namespace OpenNest.Engine.BestFit
                     }
                 }
 
+                // Phase 3: Curve-to-curve direct distance.
+                // Vertex sampling misses the true contact between two curved entities
+                // when the approach angle doesn't align with a sampled vertex.
+                for (var m = 0; m < movingCurves.Length; m++)
+                {
+                    var mc = movingCurves[m];
+                    var mcx = mc.Cx + offset.Dx;
+                    var mcy = mc.Cy + offset.Dy;
+
+                    for (var s = 0; s < stationaryCurves.Length; s++)
+                    {
+                        var sc = stationaryCurves[s];
+                        var d = SpatialQuery.RayCircleDistance(
+                            mcx, mcy, sc.Cx, sc.Cy, mc.Radius + sc.Radius, dirX, dirY);
+
+                        if (d >= minDist || d == double.MaxValue)
+                            continue;
+
+                        if (mc.Entity is Arc || sc.Entity is Arc)
+                        {
+                            var mx = mcx + d * dirX;
+                            var my = mcy + d * dirY;
+                            var toCx = sc.Cx - mx;
+                            var toCy = sc.Cy - my;
+
+                            if (mc.Entity is Arc mArc)
+                            {
+                                var angle = Angle.NormalizeRad(System.Math.Atan2(toCy, toCx));
+                                if (!Angle.IsBetweenRad(angle, mArc.StartAngle, mArc.EndAngle, mArc.IsReversed))
+                                    continue;
+                            }
+
+                            if (sc.Entity is Arc sArc)
+                            {
+                                var angle = Angle.NormalizeRad(System.Math.Atan2(-toCy, -toCx));
+                                if (!Angle.IsBetweenRad(angle, sArc.StartAngle, sArc.EndAngle, sArc.IsReversed))
+                                    continue;
+                            }
+                        }
+
+                        minDist = d;
+                        if (d <= 0) { results[i] = 0; return; }
+                    }
+                }
+
                 results[i] = minDist;
             });
 
             return results;
         }
 
+        private readonly struct CurveParams
+        {
+            public readonly Entity Entity;
+            public readonly double Cx, Cy, Radius;
+
+            public CurveParams(Entity entity, double cx, double cy, double radius)
+            {
+                Entity = entity;
+                Cx = cx;
+                Cy = cy;
+                Radius = radius;
+            }
+        }
+
+        private static CurveParams[] ExtractCurveParams(List<Entity> entities)
+        {
+            var curves = new List<CurveParams>();
+            for (var i = 0; i < entities.Count; i++)
+            {
+                if (entities[i] is Circle circle)
+                    curves.Add(new CurveParams(circle, circle.Center.X, circle.Center.Y, circle.Radius));
+                else if (entities[i] is Arc arc)
+                    curves.Add(new CurveParams(arc, arc.Center.X, arc.Center.Y, arc.Radius));
+            }
+            return curves.ToArray();
+        }
+
         private static double RayEntityDistance(
             double vx, double vy, Entity entity,
             double entityOffsetX, double entityOffsetY,

OpenNest.Engine/BestFit/PairEvaluator.cs

@@ -15,11 +15,18 @@ namespace OpenNest.Engine.BestFit
 
         public List<BestFitResult> EvaluateAll(List<PairCandidate> candidates)
         {
+            if (candidates.Count == 0)
+                return new List<BestFitResult>();
+
+            // Build a perimeter-only drawing once — all candidates share the same drawing.
+            // This avoids cloning the full program (with all cutouts) for every candidate.
+            var perimeterDrawing = CreatePerimeterDrawing(candidates[0].Drawing);
+
             var resultBag = new ConcurrentBag<BestFitResult>();
 
             Parallel.ForEach(candidates, c =>
             {
-                resultBag.Add(Evaluate(c));
+                resultBag.Add(Evaluate(c, perimeterDrawing));
             });
 
             return resultBag.ToList();
@@ -27,18 +34,24 @@ namespace OpenNest.Engine.BestFit
 
         public BestFitResult Evaluate(PairCandidate candidate)
         {
-            var drawing = candidate.Drawing;
+            var perimeterDrawing = CreatePerimeterDrawing(candidate.Drawing);
+            return Evaluate(candidate, perimeterDrawing);
+        }
 
-            var part1 = Part.CreateAtOrigin(drawing);
+        private BestFitResult Evaluate(PairCandidate candidate, Drawing perimeterDrawing)
+        {
+            var part1 = Part.CreateAtOrigin(perimeterDrawing);
 
-            var part2 = Part.CreateAtOrigin(drawing, candidate.Part2Rotation);
+            var part2 = Part.CreateAtOrigin(perimeterDrawing, candidate.Part2Rotation);
             part2.Location = candidate.Part2Offset;
             part2.UpdateBounds();
 
-            // Check overlap via shape intersection
+            // Overlap check — perimeter vs perimeter
-            var overlaps = CheckOverlap(part1, part2);
+            var shape1 = GetPerimeterShape(part1);
+            var shape2 = GetPerimeterShape(part2);
+            var overlaps = shape1 != null && shape2 != null && shape1.Intersects(shape2, out _);
 
-            // Collect all polygon vertices for convex hull / optimal rotation
+            // Convex hull vertices from perimeter polygons only
             var allPoints = GetPartVertices(part1);
             allPoints.AddRange(GetPartVertices(part2));
 
@@ -66,7 +79,7 @@ namespace OpenNest.Engine.BestFit
                 hullAngles = new List<double> { 0 };
             }
 
-            var trueArea = drawing.Area * 2;
+            var trueArea = candidate.Drawing.Area * 2;
 
             // Normalize to landscape (width >= height) for consistent display.
             if (bestHeight > bestWidth)
@@ -91,38 +104,29 @@ namespace OpenNest.Engine.BestFit
             };
         }
 
-        private bool CheckOverlap(Part part1, Part part2)
+        private static Drawing CreatePerimeterDrawing(Drawing source)
         {
-            var shapes1 = GetPartShapes(part1);
+            var entities = ConvertProgram.ToGeometry(source.Program)
-            var shapes2 = GetPartShapes(part2);
+                .Where(e => e.Layer != SpecialLayers.Rapid).ToList();
-
+            var profile = new ShapeProfile(entities);
-            for (var i = 0; i < shapes1.Count; i++)
+            var program = ConvertGeometry.ToProgram(profile.Perimeter);
-            {
+            return new Drawing(source.Name, program);
-                for (var j = 0; j < shapes2.Count; j++)
-                {
-                    List<Vector> pts;
-
-                    if (shapes1[i].Intersects(shapes2[j], out pts))
-                        return true;
-                }
-            }
-
-            return false;
         }
 
-        private List<Shape> GetPartShapes(Part part)
+        private static Shape GetPerimeterShape(Part part)
         {
             var entities = ConvertProgram.ToGeometry(part.Program)
-                .Where(e => e.Layer != SpecialLayers.Rapid);
+                .Where(e => e.Layer != SpecialLayers.Rapid).ToList();
             var shapes = ShapeBuilder.GetShapes(entities);
-            shapes.ForEach(s => s.Offset(part.Location));
+            if (shapes.Count == 0) return null;
-            return shapes;
+            shapes[0].Offset(part.Location);
+            return shapes[0];
         }
 
-        private List<Vector> GetPartVertices(Part part)
+        private static List<Vector> GetPartVertices(Part part)
         {
             var entities = ConvertProgram.ToGeometry(part.Program)
-                .Where(e => e.Layer != SpecialLayers.Rapid);
+                .Where(e => e.Layer != SpecialLayers.Rapid).ToList();
             var shapes = ShapeBuilder.GetShapes(entities);
             var points = new List<Vector>();
 
@@ -130,9 +134,7 @@ namespace OpenNest.Engine.BestFit
             {
                 var polygon = shape.ToPolygonWithTolerance(ChordTolerance);
                 polygon.Offset(part.Location);
-
+                points.AddRange(polygon.Vertices);
-                foreach (var vertex in polygon.Vertices)
-                    points.Add(vertex);
             }
 
             return points;

OpenNest.Engine/Fill/Compactor.cs

@@ -11,8 +11,6 @@ namespace OpenNest.Engine.Fill
     /// </summary>
     public static class Compactor
     {
-        private const double ChordTolerance = 0.001;
-
         public static double Push(List<Part> movingParts, Plate plate, PushDirection direction)
         {
             var obstacleParts = plate.Parts
@@ -44,7 +42,7 @@ namespace OpenNest.Engine.Fill
             var opposite = -direction;
 
             var obstacleBoxes = new Box[obstacleParts.Count];
-            var obstacleLines = new List<Line>[obstacleParts.Count];
+            var obstacleEntities = new List<Entity>[obstacleParts.Count];
 
             for (var i = 0; i < obstacleParts.Count; i++)
                 obstacleBoxes[i] = obstacleParts[i].BoundingBox;
@@ -61,7 +59,19 @@ namespace OpenNest.Engine.Fill
                     distance = edgeDist;
 
                 var movingBox = moving.BoundingBox;
-                List<Line> movingLines = null;
+                List<Entity> movingEntities = null;
+
+                // Check if any obstacle is inside the moving part — only then
+                // do we need cutout entities on the moving part.
+                var needCutouts = false;
+                for (var i = 0; i < obstacleBoxes.Length; i++)
+                {
+                    if (movingBox.Contains(obstacleBoxes[i]))
+                    {
+                        needCutouts = true;
+                        break;
+                    }
+                }
 
                 for (var i = 0; i < obstacleBoxes.Length; i++)
                 {
@@ -76,15 +86,19 @@ namespace OpenNest.Engine.Fill
                     if (!SpatialQuery.PerpendicularOverlap(movingBox, obstacleBoxes[i], direction))
                         continue;
 
-                    movingLines ??= halfSpacing > 0
+                    movingEntities ??= halfSpacing > 0
-                        ? PartGeometry.GetOffsetPartLines(moving, halfSpacing, direction, ChordTolerance)
+                        ? (needCutouts
-                        : PartGeometry.GetPartLines(moving, direction, ChordTolerance);
+                            ? PartGeometry.GetOffsetPartEntities(moving, halfSpacing)
+                            : PartGeometry.GetOffsetPerimeterEntities(moving, halfSpacing))
+                        : (needCutouts
+                            ? PartGeometry.GetPartEntities(moving)
+                            : PartGeometry.GetPerimeterEntities(moving));
 
-                    obstacleLines[i] ??= halfSpacing > 0
+                    obstacleEntities[i] ??= halfSpacing > 0
-                        ? PartGeometry.GetOffsetPartLines(obstacleParts[i], halfSpacing, opposite, ChordTolerance)
+                        ? PartGeometry.GetOffsetPerimeterEntities(obstacleParts[i], halfSpacing)
-                        : PartGeometry.GetPartLines(obstacleParts[i], opposite, ChordTolerance);
+                        : PartGeometry.GetPerimeterEntities(obstacleParts[i]);
 
-                    var d = SpatialQuery.DirectionalDistance(movingLines, obstacleLines[i], direction);
+                    var d = SpatialQuery.DirectionalDistance(movingEntities, obstacleEntities[i], direction);
                     if (d < distance)
                         distance = d;
                 }
@@ -157,7 +171,7 @@ namespace OpenNest.Engine.Fill
                         continue;
 
                     var gap = SpatialQuery.DirectionalGap(movingBox, obstacleBoxes[i], direction);
-                    var d = gap - partSpacing - 2 * ChordTolerance;
+                    var d = gap - partSpacing - 0.002;
                     if (d < 0) d = 0;
                     if (d < distance)
                         distance = d;

OpenNest.Engine/Fill/FillLinear.cs

@@ -119,10 +119,11 @@ namespace OpenNest.Engine.Fill
             var maxCopyDistance = FindMaxPairDistance(
                 patternA.Parts, boundaries, offset, pushDir, opposite, startOffset);
 
-            if (maxCopyDistance < Tolerance.Epsilon)
+            // The copy distance must be at least bboxDim + PartSpacing to prevent
-                return bboxDim + PartSpacing;
+            // bounding box overlap. Cross-pair slides can underestimate when the
-
+            // circumscribed polygon boundary overshoots the true arc, creating
-            return maxCopyDistance;
+            // spurious contacts between diagonal parts in adjacent copies.
+            return System.Math.Max(maxCopyDistance, bboxDim + PartSpacing);
         }
 
         /// <summary>

OpenNest.Engine/LeadInAssigner.cs

@@ -1,5 +1,7 @@
+using OpenNest.CNC.CuttingStrategy;
 using OpenNest.Engine.Sequencing;
 using OpenNest.Geometry;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace OpenNest.Engine
@@ -15,14 +17,28 @@ namespace OpenNest.Engine
                 return;
 
             var sequenced = Sequencer.Sequence(plate.Parts.ToList(), plate);
-            var currentPoint = PlateHelper.GetExitPoint(plate);
+            var exitPoint = PlateHelper.GetExitPoint(plate);
 
-            foreach (var sp in sequenced)
+            // Pass 1: assign lead-ins to establish pierce points
+            var piercePoints = AssignPass(sequenced, parameters, exitPoint, nextPiercePoints: null);
+
+            // Pass 2: re-assign with knowledge of next part's start point
+            AssignPass(sequenced, parameters, exitPoint, nextPiercePoints: piercePoints);
+        }
+
+        private Vector[] AssignPass(List<SequencedPart> sequenced, CuttingParameters parameters,
+            Vector exitPoint, Vector[] nextPiercePoints)
+        {
+            var piercePoints = new Vector[sequenced.Count];
+            var currentPoint = exitPoint;
+
+            for (var i = 0; i < sequenced.Count; i++)
             {
-                var part = sp.Part;
+                var part = sequenced[i].Part;
 
                 if (part.LeadInsLocked)
                 {
+                    piercePoints[i] = GetPiercePoint(part);
                     currentPoint = part.Location;
                     continue;
                 }
@@ -31,10 +47,33 @@ namespace OpenNest.Engine
                     part.RemoveLeadIns();
 
                 var localApproach = currentPoint - part.Location;
-                part.ApplyLeadIns(parameters, localApproach);
 
+                if (nextPiercePoints != null && i + 1 < sequenced.Count)
+                {
+                    var nextStart = nextPiercePoints[i + 1] - part.Location;
+                    part.ApplyLeadIns(parameters, localApproach, nextStart);
+                }
+                else
+                {
+                    part.ApplyLeadIns(parameters, localApproach);
+                }
+
+                piercePoints[i] = GetPiercePoint(part);
                 currentPoint = part.Location;
             }
+
+            return piercePoints;
+        }
+
+        private static Vector GetPiercePoint(Part part)
+        {
+            foreach (var code in part.Program.Codes)
+            {
+                if (code is CNC.Motion motion)
+                    return motion.EndPoint + part.Location;
+            }
+
+            return part.Location;
         }
     }
 }

OpenNest.Engine/MultiPlateNester.cs

@@ -19,22 +19,27 @@ namespace OpenNest
     {
         private readonly Plate _template;
         private readonly List<PlateOption> _plateOptions;
+        private readonly List<PlateOption> _sortedOptions;
         private readonly double _salvageRate;
         private readonly double _minRemnantSize;
         private readonly List<PlateResult> _platePool;
         private readonly IProgress<NestProgress> _progress;
         private readonly CancellationToken _token;
+        private readonly MultiPlateNestOptions _options;
+
+        private bool HasPlateOptions => _plateOptions != null && _plateOptions.Count > 0;
 
         private MultiPlateNester(
-            Plate template, List<PlateOption> plateOptions,
+            MultiPlateNestOptions options,
-            double salvageRate, double minRemnantSize,
             List<Plate> existingPlates,
             IProgress<NestProgress> progress, CancellationToken token)
         {
-            _template = template;
+            _options = options;
-            _plateOptions = plateOptions;
+            _template = options.Template;
-            _salvageRate = salvageRate;
+            _plateOptions = options.PlateOptions;
-            _minRemnantSize = minRemnantSize;
+            _sortedOptions = options.PlateOptions?.OrderBy(o => o.Cost).ToList();
+            _salvageRate = options.SalvageRate;
+            _minRemnantSize = options.MinRemnantSize;
             _platePool = InitializePlatePool(existingPlates);
             _progress = progress;
             _token = token;
@@ -42,26 +47,31 @@ namespace OpenNest
 
         // --- Static Utility Methods ---
 
+        public static bool FitsBounds(Box container, Box part)
+        {
+            var fitsNormal = container.Width >= part.Width - Tolerance.Epsilon
+                          && container.Length >= part.Length - Tolerance.Epsilon;
+            var fitsRotated = container.Width >= part.Length - Tolerance.Epsilon
+                           && container.Length >= part.Width - Tolerance.Epsilon;
+            return fitsNormal || fitsRotated;
+        }
+
         public static List<NestItem> SortItems(List<NestItem> items, PartSortOrder sortOrder)
         {
+            var withBounds = items.Select(i => (Item: i, Bounds: i.Drawing.Program.BoundingBox())).ToList();
+
             switch (sortOrder)
             {
                 case PartSortOrder.BoundingBoxArea:
-                    return items
+                    return withBounds
-                        .OrderByDescending(i =>
+                        .OrderByDescending(x => x.Bounds.Width * x.Bounds.Length)
-                        {
+                        .Select(x => x.Item)
-                            var bb = i.Drawing.Program.BoundingBox();
-                            return bb.Width * bb.Length;
-                        })
                         .ToList();
 
                 case PartSortOrder.Size:
-                    return items
+                    return withBounds
-                        .OrderByDescending(i =>
+                        .OrderByDescending(x => System.Math.Max(x.Bounds.Width, x.Bounds.Length))
-                        {
+                        .Select(x => x.Item)
-                            var bb = i.Drawing.Program.BoundingBox();
-                            return System.Math.Max(bb.Width, bb.Length);
-                        })
                         .ToList();
 
                 default:
@@ -126,15 +136,7 @@ namespace OpenNest
 
             foreach (var option in sorted)
             {
-                var workW = option.Width - template.EdgeSpacing.Left - template.EdgeSpacing.Right;
+                if (FitsBounds(OptionWorkArea(option, template), minBounds))
-                var workL = option.Length - template.EdgeSpacing.Top - template.EdgeSpacing.Bottom;
-
-                var fitsNormal = workW >= minBounds.Width - Tolerance.Epsilon
-                              && workL >= minBounds.Length - Tolerance.Epsilon;
-                var fitsRotated = workW >= minBounds.Length - Tolerance.Epsilon
-                               && workL >= minBounds.Width - Tolerance.Epsilon;
-
-                if (fitsNormal || fitsRotated)
                 {
                     plate.Size = new Size(option.Width, option.Length);
                     return plate;
@@ -170,32 +172,47 @@ namespace OpenNest
 
         public static MultiPlateResult Nest(
             List<NestItem> items,
-            Plate template,
+            MultiPlateNestOptions options,
-            List<PlateOption> plateOptions,
+            List<Plate> existingPlates = null,
-            double salvageRate,
+            IProgress<NestProgress> progress = null,
-            PartSortOrder sortOrder,
+            CancellationToken token = default)
-            double minRemnantSize,
-            bool allowPlateCreation,
-            List<Plate> existingPlates,
-            IProgress<NestProgress> progress,
-            CancellationToken token)
         {
-            var nester = new MultiPlateNester(template, plateOptions, salvageRate,
+            var nester = new MultiPlateNester(options, existingPlates, progress, token);
-                minRemnantSize, existingPlates, progress, token);
+            return nester.Run(items, options.SortOrder, options.AllowPlateCreation);
-            return nester.Run(items, sortOrder, allowPlateCreation);
         }
 
         // --- Private Helpers ---
 
+        private static Box OptionWorkArea(PlateOption option, Plate template)
+        {
+            var w = option.Width - template.EdgeSpacing.Left - template.EdgeSpacing.Right;
+            var h = option.Length - template.EdgeSpacing.Top - template.EdgeSpacing.Bottom;
+            return new Box(0, 0, w, h);
+        }
+
         private static double ScoreZone(Box zone, Box partBounds)
         {
-            var fitsNormal = zone.Length >= partBounds.Length && zone.Width >= partBounds.Width;
+            if (!FitsBounds(zone, partBounds))
-            var fitsRotated = zone.Length >= partBounds.Width && zone.Width >= partBounds.Length;
-
-            if (!fitsNormal && !fitsRotated)
                 return -1;
 
-            return (partBounds.Length * partBounds.Width) / zone.Area();
+            var cols = (int)(zone.Width / partBounds.Width);
+            var rows = (int)(zone.Length / partBounds.Length);
+            var colsR = (int)(zone.Width / partBounds.Length);
+            var rowsR = (int)(zone.Length / partBounds.Width);
+            var estimatedCount = System.Math.Max(cols * rows, colsR * rowsR);
+
+            var utilization = (estimatedCount * partBounds.Width * partBounds.Length) / zone.Area();
+
+            var zoneAspect = zone.Width / zone.Length;
+            var partAspect = partBounds.Width / partBounds.Length;
+            var aspectMatch = System.Math.Min(zoneAspect, partAspect) / System.Math.Max(zoneAspect, partAspect);
+
+            return utilization * 0.7 + aspectMatch * 0.3;
+        }
+
+        private static void DecrementQuantity(NestItem item, int placed)
+        {
+            item.Quantity = System.Math.Max(0, item.Quantity - placed);
         }
 
         private int FillAndPlace(PlateResult pr, Box zone, NestItem item)
@@ -206,9 +223,8 @@ namespace OpenNest
 
             if (parts.Count > 0)
             {
-                pr.Plate.Parts.AddRange(parts);
+                pr.AddParts(parts);
-                pr.Parts.AddRange(parts);
+                DecrementQuantity(item, parts.Count);
-                item.Quantity = System.Math.Max(0, item.Quantity - parts.Count);
             }
 
             return parts.Count;
@@ -218,7 +234,7 @@ namespace OpenNest
         {
             var pr = new PlateResult { Plate = plate, IsNew = true };
 
-            if (_plateOptions != null)
+            if (HasPlateOptions)
             {
                 pr.ChosenSize = _plateOptions.FirstOrDefault(o =>
                     o.Width.IsEqualTo(plate.Size.Width) && o.Length.IsEqualTo(plate.Size.Length));
@@ -253,6 +269,29 @@ namespace OpenNest
             return pool;
         }
 
+        private bool TryWithUpgradedSize(PlateResult pr, PlateOption upgradeOption, Func<List<Box>, bool> tryFill)
+        {
+            var oldSize = pr.Plate.Size;
+            var oldChosenSize = pr.ChosenSize;
+
+            pr.Plate.Size = new Size(upgradeOption.Width, upgradeOption.Length);
+            pr.ChosenSize = upgradeOption;
+
+            var remnants = RemnantFinder.FromPlate(pr.Plate).FindRemnants();
+
+            if (remnants.Count > 0 && tryFill(remnants))
+                return true;
+
+            pr.Plate.Size = oldSize;
+            pr.ChosenSize = oldChosenSize;
+            return false;
+        }
+
+        private PlateOption FindSmallestFittingOption(Box partBounds)
+        {
+            return _sortedOptions?.FirstOrDefault(o => FitsBounds(OptionWorkArea(o, _template), partBounds));
+        }
+
         // --- Orchestration ---
 
         private MultiPlateResult Run(List<NestItem> items, PartSortOrder sortOrder, bool allowPlateCreation)
@@ -279,7 +318,7 @@ namespace OpenNest
                 {
                     PlaceOnNewPlates(item, bb);
 
-                    if (item.Quantity > 0 && _plateOptions != null && _plateOptions.Count > 0)
+                    if (item.Quantity > 0 && HasPlateOptions)
                         TryUpgradeOrNewPlate(item, bb);
                 }
             }
@@ -292,7 +331,7 @@ namespace OpenNest
                 CreateSharedPlates(leftovers);
             }
 
-            if (_plateOptions != null && _plateOptions.Count > 0 && !_token.IsCancellationRequested)
+            if (HasPlateOptions && !_token.IsCancellationRequested)
                 TryConsolidateTailPlates();
 
             foreach (var item in sorted.Where(i => i.Quantity > 0))
@@ -323,19 +362,26 @@ namespace OpenNest
                         break;
 
                     var engine = NestEngineRegistry.Create(pr.Plate);
-                    var cloned = remaining.Select(CloneItem).ToList();
-                    var parts = engine.PackArea(remnants[0], cloned, _progress, _token);
 
-                    if (parts.Count > 0)
+                    foreach (var remnant in remnants)
                     {
-                        pr.Plate.Parts.AddRange(parts);
+                        remaining = leftovers.Where(i => i.Quantity > 0).ToList();
-                        pr.Parts.AddRange(parts);
+                        if (remaining.Count == 0)
-                        anyPlaced = true;
+                            break;
 
-                        foreach (var item in remaining)
+                        var cloned = remaining.Select(CloneItem).ToList();
+                        var parts = engine.PackArea(remnant, cloned, _progress, _token);
+
+                        if (parts.Count > 0)
                         {
-                            var placed = parts.Count(p => p.BaseDrawing.Name == item.Drawing.Name);
+                            pr.AddParts(parts);
-                            item.Quantity = System.Math.Max(0, item.Quantity - placed);
+                            anyPlaced = true;
+
+                            foreach (var item in remaining)
+                            {
+                                var placed = parts.Count(p => p.BaseDrawing == item.Drawing);
+                                DecrementQuantity(item, placed);
+                            }
                         }
                     }
                 }
@@ -349,6 +395,7 @@ namespace OpenNest
             while (leftovers.Count > 0 && !_token.IsCancellationRequested)
             {
                 var plate = CreatePlate(_template, _plateOptions, null);
+                var pr = CreateNewPlateResult(plate);
                 var placedAny = false;
 
                 foreach (var item in leftovers)
@@ -364,22 +411,27 @@ namespace OpenNest
                         break;
 
                     var engine = NestEngineRegistry.Create(plate);
-                    var clonedItem = CloneItem(item);
-                    var parts = engine.Fill(clonedItem, remnants[0], _progress, _token);
 
-                    if (parts.Count > 0)
+                    foreach (var remnant in remnants)
                     {
-                        plate.Parts.AddRange(parts);
+                        if (item.Quantity <= 0)
-                        item.Quantity = System.Math.Max(0, item.Quantity - parts.Count);
+                            break;
-                        placedAny = true;
+
+                        var clonedItem = CloneItem(item);
+                        var parts = engine.Fill(clonedItem, remnant, _progress, _token);
+
+                        if (parts.Count > 0)
+                        {
+                            pr.AddParts(parts);
+                            DecrementQuantity(item, parts.Count);
+                            placedAny = true;
+                        }
                     }
                 }
 
                 if (!placedAny)
                     break;
 
-                var pr = CreateNewPlateResult(plate);
-                pr.Parts.AddRange(plate.Parts);
                 _platePool.Add(pr);
                 leftovers.RemoveAll(i => i.Quantity <= 0);
             }
@@ -388,6 +440,8 @@ namespace OpenNest
         private bool TryPlaceOnExistingPlates(NestItem item, Box partBounds)
         {
             var anyPlaced = false;
+            var remnantCache = new Dictionary<PlateResult, List<Box>>();
+            PlateResult lastModified = null;
 
             while (item.Quantity > 0 && !_token.IsCancellationRequested)
             {
@@ -400,14 +454,17 @@ namespace OpenNest
                     if (_token.IsCancellationRequested)
                         break;
 
-                    var workArea = pr.Plate.WorkArea();
+                    if (pr == lastModified || !remnantCache.ContainsKey(pr))
-                    var classification = Classify(partBounds, workArea);
+                    {
+                        var workArea = pr.Plate.WorkArea();
+                        var classification = Classify(partBounds, workArea);
 
-                    var remnants = classification == PartClass.Small
+                        remnantCache[pr] = classification == PartClass.Small
-                        ? FindRemnants(pr.Plate, _minRemnantSize, scrapOnly: true)
+                            ? FindRemnants(pr.Plate, _minRemnantSize, scrapOnly: true)
-                        : FindRemnants(pr.Plate, _minRemnantSize, scrapOnly: false);
+                            : FindRemnants(pr.Plate, _minRemnantSize, scrapOnly: false);
+                    }
 
-                    foreach (var zone in remnants)
+                    foreach (var zone in remnantCache[pr])
                     {
                         var score = ScoreZone(zone, partBounds);
                         if (score > bestScore)
@@ -425,6 +482,7 @@ namespace OpenNest
                 if (FillAndPlace(bestPlate, bestZone, item) == 0)
                     break;
 
+                lastModified = bestPlate;
                 anyPlaced = true;
             }
 
@@ -440,9 +498,7 @@ namespace OpenNest
                 var plate = CreatePlate(_template, _plateOptions, partBounds);
                 var workArea = plate.WorkArea();
 
-                if (partBounds.Length > workArea.Length && partBounds.Length > workArea.Width)
+                if (!FitsBounds(workArea, partBounds))
-                    break;
-                if (partBounds.Width > workArea.Width && partBounds.Width > workArea.Length)
                     break;
 
                 var pr = CreateNewPlateResult(plate);
@@ -459,36 +515,27 @@ namespace OpenNest
 
         private bool TryUpgradeOrNewPlate(NestItem item, Box partBounds)
         {
-            if (_plateOptions == null || _plateOptions.Count == 0)
+            if (!HasPlateOptions)
                 return false;
 
-            var sortedOptions = _plateOptions.OrderBy(o => o.Cost).ToList();
-
             foreach (var pr in _platePool.Where(p => p.IsNew && p.ChosenSize != null))
             {
                 var currentOption = pr.ChosenSize;
-                var currentIdx = sortedOptions.FindIndex(o =>
+                var currentIdx = _sortedOptions.FindIndex(o =>
                     o.Width.IsEqualTo(currentOption.Width) && o.Length.IsEqualTo(currentOption.Length));
 
-                if (currentIdx < 0 || currentIdx >= sortedOptions.Count - 1)
+                if (currentIdx < 0 || currentIdx >= _sortedOptions.Count - 1)
                     continue;
 
-                for (var i = currentIdx + 1; i < sortedOptions.Count; i++)
+                for (var i = currentIdx + 1; i < _sortedOptions.Count; i++)
                 {
-                    var upgradeOption = sortedOptions[i];
+                    var upgradeOption = _sortedOptions[i];
 
-                    // Only consider options that are at least as large in both dimensions.
                     if (upgradeOption.Width < currentOption.Width - Tolerance.Epsilon
                         || upgradeOption.Length < currentOption.Length - Tolerance.Epsilon)
                         continue;
 
-                    var smallestNew = sortedOptions.FirstOrDefault(o =>
+                    var smallestNew = FindSmallestFittingOption(partBounds);
-                    {
-                        var ww = o.Width - _template.EdgeSpacing.Left - _template.EdgeSpacing.Right;
-                        var wl = o.Length - _template.EdgeSpacing.Top - _template.EdgeSpacing.Bottom;
-                        return (ww >= partBounds.Width && wl >= partBounds.Length)
-                            || (ww >= partBounds.Length && wl >= partBounds.Width);
-                    });
 
                     if (smallestNew == null)
                         continue;
@@ -499,22 +546,19 @@ namespace OpenNest
 
                     if (decision.ShouldUpgrade)
                     {
-                        var oldSize = pr.Plate.Size;
+                        var placed = TryWithUpgradedSize(pr, upgradeOption, remnants =>
-                        var oldChosenSize = pr.ChosenSize;
+                        {
+                            foreach (var remnant in remnants)
+                            {
+                                if (FillAndPlace(pr, remnant, item) > 0)
+                                    return true;
+                            }
+                            return false;
+                        });
 
-                        pr.Plate.Size = new Size(upgradeOption.Width, upgradeOption.Length);
+                        if (placed)
-                        pr.ChosenSize = upgradeOption;
-
-                        var remainingArea = RemnantFinder.FromPlate(pr.Plate).FindRemnants();
-
-                        if (remainingArea.Count > 0 && FillAndPlace(pr, remainingArea[0], item) > 0)
                             return true;
-
-                        // Revert if nothing was placed.
-                        pr.Plate.Size = oldSize;
-                        pr.ChosenSize = oldChosenSize;
                     }
-                    break;
                 }
             }
 
@@ -523,73 +567,93 @@ namespace OpenNest
 
         private void TryConsolidateTailPlates()
         {
-            var activePlates = _platePool.Where(p => p.Parts.Count > 0 && p.IsNew).ToList();
+            var consolidated = true;
-            if (activePlates.Count < 2)
+            while (consolidated)
-                return;
-
-            var sortedOptions = _plateOptions.OrderBy(o => o.Cost).ToList();
-
-            // Try to absorb the smallest-utilization new plate into another plate via upgrade.
-            var donor = activePlates.OrderBy(p => p.Plate.Utilization()).First();
-            var donorParts = donor.Parts.ToList();
-
-            foreach (var target in activePlates)
             {
-                if (target == donor || target.ChosenSize == null)
+                consolidated = false;
-                    continue;
 
-                var currentOption = target.ChosenSize;
+                var activePlates = _platePool.Where(p => p.Parts.Count > 0 && p.IsNew).ToList();
+                if (activePlates.Count < 2)
+                    return;
 
-                // Try each larger option that doesn't shrink any dimension.
+                var donors = activePlates.OrderBy(p => p.Plate.Utilization()).ToList();
-                foreach (var upgradeOption in sortedOptions.Where(o =>
+
-                    o.Width >= currentOption.Width - Tolerance.Epsilon
+                foreach (var donor in donors)
-                    && o.Length >= currentOption.Length - Tolerance.Epsilon
-                    && (o.Width > currentOption.Width + Tolerance.Epsilon
-                        || o.Length > currentOption.Length + Tolerance.Epsilon)))
                 {
-                    var oldSize = target.Plate.Size;
+                    if (donor.Parts.Count == 0)
-                    var oldChosenSize = target.ChosenSize;
-
-                    target.Plate.Size = new Size(upgradeOption.Width, upgradeOption.Length);
-                    target.ChosenSize = upgradeOption;
-
-                    var remnants = RemnantFinder.FromPlate(target.Plate).FindRemnants();
-                    if (remnants.Count == 0)
-                    {
-                        target.Plate.Size = oldSize;
-                        target.ChosenSize = oldChosenSize;
                         continue;
-                    }
 
-                    // Try to pack all donor parts into the remnant space.
+                    var donorParts = donor.Parts.ToList();
-                    var engine = NestEngineRegistry.Create(target.Plate);
+                    var absorbed = false;
-                    var tempItems = donorParts
-                        .GroupBy(p => p.BaseDrawing.Name)
-                        .Select(g => new NestItem
-                        {
-                            Drawing = g.First().BaseDrawing,
-                            Quantity = g.Count(),
-                        })
-                        .ToList();
 
-                    var placed = engine.PackArea(remnants[0], tempItems, _progress, _token);
+                    foreach (var target in activePlates)
-
-                    if (placed.Count >= donorParts.Count)
                     {
-                        // All donor parts fit — absorb them.
+                        if (target == donor || target.ChosenSize == null || target.Parts.Count == 0)
-                        target.Plate.Parts.AddRange(placed);
+                            continue;
-                        target.Parts.AddRange(placed);
 
-                        foreach (var p in donorParts)
+                        var currentOption = target.ChosenSize;
-                            donor.Plate.Parts.Remove(p);
+
-                        donor.Parts.Clear();
+                        foreach (var upgradeOption in _sortedOptions.Where(o =>
-                        _platePool.Remove(donor);
+                            o.Width >= currentOption.Width - Tolerance.Epsilon
-                        return;
+                            && o.Length >= currentOption.Length - Tolerance.Epsilon
+                            && (o.Width > currentOption.Width + Tolerance.Epsilon
+                                || o.Length > currentOption.Length + Tolerance.Epsilon)))
+                        {
+                            absorbed = TryWithUpgradedSize(target, upgradeOption, remnants =>
+                            {
+                                var engine = NestEngineRegistry.Create(target.Plate);
+                                var tempItems = donorParts
+                                    .GroupBy(p => p.BaseDrawing)
+                                    .Select(g => new NestItem
+                                    {
+                                        Drawing = g.Key,
+                                        Quantity = g.Count(),
+                                    })
+                                    .ToList();
+
+                                var totalPlaced = new List<Part>();
+                                foreach (var remnant in remnants)
+                                {
+                                    var placed = engine.PackArea(remnant, tempItems, _progress, _token);
+                                    totalPlaced.AddRange(placed);
+
+                                    foreach (var ti in tempItems)
+                                    {
+                                        var count = placed.Count(p => p.BaseDrawing == ti.Drawing);
+                                        ti.Quantity = System.Math.Max(0, ti.Quantity - count);
+                                    }
+
+                                    if (tempItems.All(ti => ti.Quantity <= 0))
+                                        break;
+                                }
+
+                                if (totalPlaced.Count >= donorParts.Count)
+                                {
+                                    target.AddParts(totalPlaced);
+
+                                    foreach (var p in donorParts)
+                                        donor.Plate.Parts.Remove(p);
+                                    donor.Parts.Clear();
+                                    _platePool.Remove(donor);
+                                    return true;
+                                }
+
+                                return false;
+                            });
+
+                            if (absorbed)
+                                break;
+                        }
+
+                        if (absorbed)
+                            break;
                     }
 
-                    // Didn't fit all parts — revert.
+                    if (absorbed)
-                    target.Plate.Size = oldSize;
+                    {
-                    target.ChosenSize = oldChosenSize;
+                        consolidated = true;
+                        break;
+                    }
                 }
             }
         }

OpenNest.Engine/MultiPlateResult.cs

@@ -2,6 +2,16 @@ using System.Collections.Generic;
 
 namespace OpenNest
 {
+    public class MultiPlateNestOptions
+    {
+        public Plate Template { get; set; }
+        public List<PlateOption> PlateOptions { get; set; }
+        public double SalvageRate { get; set; } = 0.5;
+        public PartSortOrder SortOrder { get; set; } = PartSortOrder.BoundingBoxArea;
+        public double MinRemnantSize { get; set; } = 12.0;
+        public bool AllowPlateCreation { get; set; } = true;
+    }
+
     public class MultiPlateResult
     {
         public List<PlateResult> Plates { get; set; } = new();
@@ -14,5 +24,11 @@ namespace OpenNest
         public List<Part> Parts { get; set; } = new();
         public PlateOption ChosenSize { get; set; }
         public bool IsNew { get; set; }
+
+        public void AddParts(IList<Part> parts)
+        {
+            Plate.Parts.AddRange(parts);
+            Parts.AddRange(parts);
+        }
     }
 }

OpenNest.Engine/PlateProcessingResult.cs

@@ -4,7 +4,7 @@ using System.Collections.Generic;
 
 namespace OpenNest.Engine
 {
-    public class PlateResult
+    public class PlateProcessingResult
     {
         public List<ProcessedPart> Parts { get; init; }
     }

OpenNest.Engine/PlateProcessor.cs

@@ -14,18 +14,41 @@ namespace OpenNest.Engine
         public ContourCuttingStrategy CuttingStrategy { get; set; }
         public IRapidPlanner RapidPlanner { get; set; }
 
-        public PlateResult Process(Plate plate)
+        public PlateProcessingResult Process(Plate plate)
         {
             var sequenced = Sequencer.Sequence(plate.Parts.ToList(), plate);
+            var exitPoint = PlateHelper.GetExitPoint(plate);
+
+            // Pass 1: process each part to collect pierce points
+            var piercePoints = new Vector[sequenced.Count];
+            var currentPoint = exitPoint;
+
+            for (var i = 0; i < sequenced.Count; i++)
+            {
+                var part = sequenced[i].Part;
+
+                if (!part.HasManualLeadIns && CuttingStrategy != null)
+                {
+                    var localApproach = ToPartLocal(currentPoint, part);
+                    var result = CuttingStrategy.Apply(part.Program, localApproach);
+                    piercePoints[i] = ToPlateSpace(GetProgramStartPoint(result.Program), part);
+                    currentPoint = ToPlateSpace(result.LastCutPoint, part);
+                }
+                else
+                {
+                    piercePoints[i] = ToPlateSpace(GetProgramStartPoint(part.Program), part);
+                    currentPoint = ToPlateSpace(GetProgramEndPoint(part.Program), part);
+                }
+            }
+
+            // Pass 2: re-process with next part's start point for perimeter lead-in refinement
             var results = new List<ProcessedPart>(sequenced.Count);
             var cutAreas = new List<Shape>();
-            var currentPoint = PlateHelper.GetExitPoint(plate);
+            currentPoint = exitPoint;
 
-            foreach (var sp in sequenced)
+            for (var i = 0; i < sequenced.Count; i++)
             {
-                var part = sp.Part;
+                var part = sequenced[i].Part;
-
-                // Compute approach point in part-local space
                 var localApproach = ToPartLocal(currentPoint, part);
 
                 Program processedProgram;
@@ -33,7 +56,18 @@ namespace OpenNest.Engine
 
                 if (!part.HasManualLeadIns && CuttingStrategy != null)
                 {
-                    var cuttingResult = CuttingStrategy.Apply(part.Program, localApproach);
+                    CuttingResult cuttingResult;
+
+                    if (i + 1 < sequenced.Count)
+                    {
+                        var nextStart = ToPartLocal(piercePoints[i + 1], part);
+                        cuttingResult = CuttingStrategy.Apply(part.Program, localApproach, nextStart);
+                    }
+                    else
+                    {
+                        cuttingResult = CuttingStrategy.Apply(part.Program, localApproach);
+                    }
+
                     processedProgram = cuttingResult.Program;
                     lastCutLocal = cuttingResult.LastCutPoint;
                 }
@@ -43,11 +77,9 @@ namespace OpenNest.Engine
                     lastCutLocal = GetProgramEndPoint(part.Program);
                 }
 
-                // Pierce point: program start point in plate space
                 var pierceLocal = GetProgramStartPoint(processedProgram);
                 var piercePoint = ToPlateSpace(pierceLocal, part);
 
-                // Plan rapid from currentPoint to pierce point
                 var rapidPath = RapidPlanner.Plan(currentPoint, piercePoint, cutAreas);
 
                 results.Add(new ProcessedPart
@@ -57,16 +89,14 @@ namespace OpenNest.Engine
                     RapidPath = rapidPath
                 });
 
-                // Update cut areas with part perimeter
                 var perimeter = GetPartPerimeter(part);
                 if (perimeter != null)
                     cutAreas.Add(perimeter);
 
-                // Update current point to last cut point in plate space
                 currentPoint = ToPlateSpace(lastCutLocal, part);
             }
 
-            return new PlateResult { Parts = results };
+            return new PlateProcessingResult { Parts = results };
         }
 
         private static Vector ToPartLocal(Vector platePoint, Part part)

OpenNest.Engine/Strategies/FillContext.cs

@@ -15,7 +15,7 @@ namespace OpenNest.Engine.Strategies
         public int PlateNumber { get; init; }
         public CancellationToken Token { get; init; }
         public IProgress<NestProgress> Progress { get; init; }
-        public FillPolicy Policy { get; init; }
+        public FillPolicy Policy { get; init; } = new FillPolicy(new DefaultFillComparer());
         public int MaxQuantity { get; init; }
         public PartType PartType { get; set; }
 

OpenNest.IO/CadImportOptions.cs

@@ -0,0 +1,39 @@
+namespace OpenNest.IO
+{
+    /// <summary>
+    /// Options controlling how <see cref="CadImporter"/> loads a CAD file
+    /// and builds a <see cref="Drawing"/>.
+    /// </summary>
+    public class CadImportOptions
+    {
+        /// <summary>
+        /// Detector name to use for bend detection. Null = auto-detect.
+        /// </summary>
+        public string BendDetectorName { get; set; }
+
+        /// <summary>
+        /// When false, skips bend detection entirely. Default true.
+        /// </summary>
+        public bool DetectBends { get; set; } = true;
+
+        /// <summary>
+        /// Override the drawing name. Null = filename without extension.
+        /// </summary>
+        public string Name { get; set; }
+
+        /// <summary>
+        /// Required quantity on the produced drawing. Default 1.
+        /// </summary>
+        public int Quantity { get; set; } = 1;
+
+        /// <summary>
+        /// Customer name on the produced drawing. Default null.
+        /// </summary>
+        public string Customer { get; set; }
+
+        /// <summary>
+        /// Returns a default options instance.
+        /// </summary>
+        public static CadImportOptions Default => new CadImportOptions();
+    }
+}

OpenNest.IO/CadImportResult.cs

@@ -0,0 +1,42 @@
+using System.Collections.Generic;
+using OpenNest.Bending;
+using OpenNest.Geometry;
+
+namespace OpenNest.IO
+{
+    /// <summary>
+    /// Intermediate result of <see cref="CadImporter.Import"/>. Holds raw loaded
+    /// geometry and detected bends. Callers may mutate <see cref="Entities"/> and
+    /// <see cref="Bends"/> before passing to <see cref="CadImporter.BuildDrawing"/>.
+    /// </summary>
+    public class CadImportResult
+    {
+        /// <summary>
+        /// All entities loaded from the source file, including promoted bend
+        /// source entities. Mutable.
+        /// </summary>
+        public List<Entity> Entities { get; set; } = new List<Entity>();
+
+        /// <summary>
+        /// Bends detected during import. Mutable — callers may add, remove,
+        /// or replace entries before building the drawing.
+        /// </summary>
+        public List<Bend> Bends { get; set; } = new List<Bend>();
+
+        /// <summary>
+        /// Bounding box of <see cref="Entities"/> at import time. May be stale
+        /// if callers mutate <see cref="Entities"/>; recompute if needed.
+        /// </summary>
+        public Box Bounds { get; set; }
+
+        /// <summary>
+        /// Absolute path to the source file.
+        /// </summary>
+        public string SourcePath { get; set; }
+
+        /// <summary>
+        /// Default drawing name (filename without extension, unless overridden).
+        /// </summary>
+        public string Name { get; set; }
+    }
+}

OpenNest.IO/CadImporter.cs

@@ -0,0 +1,140 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using OpenNest.Bending;
+using OpenNest.Converters;
+using OpenNest.Geometry;
+using OpenNest.IO.Bending;
+
+namespace OpenNest.IO
+{
+    /// <summary>
+    /// Shared service that converts a CAD source file into a fully-populated
+    /// <see cref="Drawing"/>. Used by the UI, console, MCP, API, and training
+    /// tools so all code paths produce identical drawings.
+    /// </summary>
+    public static class CadImporter
+    {
+        /// <summary>
+        /// Load a DXF file, run bend detection, and return a mutable result
+        /// ready for interactive editing or direct conversion to a Drawing.
+        /// </summary>
+        public static CadImportResult Import(string path, CadImportOptions options = null)
+        {
+            options ??= CadImportOptions.Default;
+
+            var dxf = Dxf.Import(path);
+
+            var bends = new List<Bend>();
+            if (options.DetectBends && dxf.Document != null)
+            {
+                bends = options.BendDetectorName == null
+                    ? BendDetectorRegistry.AutoDetect(dxf.Document)
+                    : BendDetectorRegistry.GetByName(options.BendDetectorName)
+                        ?.DetectBends(dxf.Document)
+                      ?? new List<Bend>();
+            }
+
+            Bend.UpdateEtchEntities(dxf.Entities, bends);
+
+            return new CadImportResult
+            {
+                Entities = dxf.Entities,
+                Bends = bends,
+                Bounds = dxf.Entities.GetBoundingBox(),
+                SourcePath = path,
+                Name = options.Name ?? Path.GetFileNameWithoutExtension(path),
+            };
+        }
+
+        /// <summary>
+        /// Convenience for headless callers: Import a file and build a Drawing
+        /// in a single call, using all loaded entities and detected bends.
+        /// </summary>
+        public static Drawing ImportDrawing(string path, CadImportOptions options = null)
+        {
+            options ??= CadImportOptions.Default;
+            var result = Import(path, options);
+            return BuildDrawing(
+                result,
+                result.Entities,
+                result.Bends,
+                options.Quantity,
+                options.Customer,
+                editedProgram: null);
+        }
+
+        /// <summary>
+        /// Build a fully-populated <see cref="Drawing"/> from an import result plus
+        /// the caller's current entity and bend state. UI callers pass the currently
+        /// visible subset; headless callers pass the full lists.
+        ///
+        /// The produced drawing has:
+        /// - Program generated from the visible entities, with its first rapid moved
+        ///   to the origin and the pierce location stored in Source.Offset
+        /// - SourceEntities containing all non-bend-source entities from the result
+        /// - SuppressedEntityIds containing entities whose layer or IsVisible is false
+        /// - Bends copied from the provided list
+        /// - Customer, Quantity, Source.Path from options / result
+        /// </summary>
+        /// <param name="result">Import result from <see cref="Import"/>.</param>
+        /// <param name="entities">
+        /// Entities to build the program from. Typically the currently visible subset.
+        /// </param>
+        /// <param name="bends">Bends to attach to the drawing.</param>
+        /// <param name="quantity">Required quantity.</param>
+        /// <param name="customer">Customer name, or null.</param>
+        /// <param name="editedProgram">
+        /// When non-null, replaces the generated program (used by the UI to honor
+        /// in-place G-code edits). Source.Offset is still populated from the
+        /// generated program so round-trips stay consistent.
+        /// </param>
+        public static Drawing BuildDrawing(
+            CadImportResult result,
+            IEnumerable<Entity> entities,
+            IEnumerable<Bend> bends,
+            int quantity,
+            string customer,
+            OpenNest.CNC.Program editedProgram)
+        {
+            var visible = entities as IList<Entity> ?? new List<Entity>(entities);
+            var bendList = bends as IList<Bend> ?? new List<Bend>(bends);
+
+            var normalized = ShapeProfile.NormalizeEntities(visible);
+            var pgm = ConvertGeometry.ToProgram(normalized);
+
+            var offset = Vector.Zero;
+            if (pgm != null && pgm.Codes.Count > 0 && pgm[0].Type == OpenNest.CNC.CodeType.RapidMove)
+            {
+                var rapid = (OpenNest.CNC.RapidMove)pgm[0];
+                offset = rapid.EndPoint;
+                pgm.Offset(-offset);
+            }
+
+            var drawing = new Drawing(result.Name)
+            {
+                Color = Drawing.GetNextColor(),
+                Customer = customer,
+            };
+            drawing.Source.Path = result.SourcePath;
+            drawing.Source.Offset = offset;
+            drawing.Quantity.Required = quantity;
+            drawing.Bends.AddRange(bendList);
+            drawing.Program = editedProgram ?? pgm;
+
+            var bendSources = new HashSet<Entity>(
+                bendList.Where(b => b.SourceEntity != null).Select(b => b.SourceEntity));
+
+            drawing.SourceEntities = result.Entities
+                .Where(e => !bendSources.Contains(e))
+                .ToList();
+
+            drawing.SuppressedEntityIds = new HashSet<System.Guid>(
+                drawing.SourceEntities
+                    .Where(e => !(e.Layer != null && e.Layer.IsVisible && e.IsVisible))
+                    .Select(e => e.Id));
+
+            return drawing;
+        }
+    }
+}

OpenNest.IO/EntitySerializer.cs

@@ -0,0 +1,139 @@
+using OpenNest.Geometry;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using static OpenNest.IO.NestFormat;
+
+namespace OpenNest.IO
+{
+    public static class EntitySerializer
+    {
+        public static EntitySetDto ToDto(List<Entity> entities, HashSet<Guid> suppressed)
+        {
+            return new EntitySetDto
+            {
+                Entities = entities.Select(ToEntityDto).ToList(),
+                Suppressed = suppressed.Select(id => id.ToString()).ToList()
+            };
+        }
+
+        public static (List<Entity> entities, HashSet<Guid> suppressed) FromDto(EntitySetDto dto)
+        {
+            var entities = dto.Entities.Select(FromEntityDto).ToList();
+            var suppressed = new HashSet<Guid>(dto.Suppressed.Select(Guid.Parse));
+            return (entities, suppressed);
+        }
+
+        private static EntityDto ToEntityDto(Entity entity)
+        {
+            switch (entity.Type)
+            {
+                case EntityType.Line:
+                    var line = (Line)entity;
+                    return new EntityDto
+                    {
+                        Id = entity.Id.ToString(),
+                        Type = "line",
+                        Layer = entity.Layer?.Name ?? "",
+                        LineType = entity.LineTypeName ?? "",
+                        X1 = line.StartPoint.X,
+                        Y1 = line.StartPoint.Y,
+                        X2 = line.EndPoint.X,
+                        Y2 = line.EndPoint.Y
+                    };
+
+                case EntityType.Arc:
+                    var arc = (Arc)entity;
+                    return new EntityDto
+                    {
+                        Id = entity.Id.ToString(),
+                        Type = "arc",
+                        Layer = entity.Layer?.Name ?? "",
+                        LineType = entity.LineTypeName ?? "",
+                        CX = arc.Center.X,
+                        CY = arc.Center.Y,
+                        R = arc.Radius,
+                        StartAngle = arc.StartAngle,
+                        EndAngle = arc.EndAngle,
+                        Reversed = arc.IsReversed
+                    };
+
+                case EntityType.Circle:
+                    var circle = (Circle)entity;
+                    return new EntityDto
+                    {
+                        Id = entity.Id.ToString(),
+                        Type = "circle",
+                        Layer = entity.Layer?.Name ?? "",
+                        LineType = entity.LineTypeName ?? "",
+                        CX = circle.Center.X,
+                        CY = circle.Center.Y,
+                        R = circle.Radius,
+                        Rotation = circle.Rotation == RotationType.CW ? "CW" : "CCW"
+                    };
+
+                default:
+                    throw new NotSupportedException($"Entity type {entity.Type} is not supported for serialization.");
+            }
+        }
+
+        private static Entity FromEntityDto(EntityDto dto)
+        {
+            Entity entity;
+
+            switch (dto.Type)
+            {
+                case "line":
+                    entity = new Line(
+                        new Vector(dto.X1, dto.Y1),
+                        new Vector(dto.X2, dto.Y2));
+                    break;
+
+                case "arc":
+                    entity = new Arc(
+                        new Vector(dto.CX, dto.CY),
+                        dto.R,
+                        dto.StartAngle,
+                        dto.EndAngle,
+                        dto.Reversed);
+                    break;
+
+                case "circle":
+                    var circle = new Circle(new Vector(dto.CX, dto.CY), dto.R);
+                    circle.Rotation = dto.Rotation == "CW" ? RotationType.CW : RotationType.CCW;
+                    entity = circle;
+                    break;
+
+                default:
+                    throw new NotSupportedException($"Entity type '{dto.Type}' is not supported for deserialization.");
+            }
+
+            entity.Id = Guid.Parse(dto.Id);
+            entity.Layer = ResolveLayer(dto.Layer);
+            entity.LineTypeName = dto.LineType;
+
+            return entity;
+        }
+
+        private static Layer ResolveLayer(string name)
+        {
+            if (string.IsNullOrEmpty(name) || name == "0")
+                return Layer.Default;
+
+            if (string.Equals(name, SpecialLayers.Cut.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Cut;
+            if (string.Equals(name, SpecialLayers.Rapid.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Rapid;
+            if (string.Equals(name, SpecialLayers.Display.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Display;
+            if (string.Equals(name, SpecialLayers.Leadin.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Leadin;
+            if (string.Equals(name, SpecialLayers.Leadout.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Leadout;
+            if (string.Equals(name, SpecialLayers.Scribe.Name, StringComparison.OrdinalIgnoreCase))
+                return SpecialLayers.Scribe;
+
+            return new Layer(name);
+        }
+    }
+}

OpenNest.IO/NestFormat.cs

@@ -162,6 +162,35 @@ namespace OpenNest.IO
             public double Cost { get; init; }
         }
 
+        public record EntitySetDto
+        {
+            public List<EntityDto> Entities { get; init; } = new();
+            public List<string> Suppressed { get; init; } = new();
+        }
+
+        public record EntityDto
+        {
+            public string Id { get; init; } = "";
+            public string Type { get; init; } = "";
+            public string Layer { get; init; } = "";
+            public string LineType { get; init; } = "";
+
+            // Line
+            public double X1 { get; init; }
+            public double Y1 { get; init; }
+            public double X2 { get; init; }
+            public double Y2 { get; init; }
+
+            // Arc / Circle
+            public double CX { get; init; }
+            public double CY { get; init; }
+            public double R { get; init; }
+            public double StartAngle { get; init; }
+            public double EndAngle { get; init; }
+            public bool Reversed { get; init; }
+            public string Rotation { get; init; } = "";
+        }
+
         public record BestFitSetDto
         {
             public double PlateWidth { get; init; }

OpenNest.IO/NestReader.cs

@@ -36,7 +36,8 @@ namespace OpenNest.IO
             var dto = JsonSerializer.Deserialize<NestDto>(nestJson, JsonOptions);
 
             var programs = ReadPrograms(dto.Drawings.Count);
-            var drawingMap = BuildDrawings(dto, programs);
+            var entitySets = ReadEntitySets(dto.Drawings.Count);
+            var drawingMap = BuildDrawings(dto, programs, entitySets);
             ReadBestFits(drawingMap);
             var nest = BuildNest(dto, drawingMap);
 
@@ -70,11 +71,87 @@ namespace OpenNest.IO
 
                 var reader = new ProgramReader(memStream);
                 programs[i] = reader.Read();
+
+                // Read sub-programs if present
+                var subsEntry = zipArchive.GetEntry($"programs/program-{i}-subs");
+                if (subsEntry != null)
+                {
+                    using var subsStream = subsEntry.Open();
+                    ReadSubPrograms(programs[i], subsStream);
+                }
             }
             return programs;
         }
 
-        private Dictionary<int, Drawing> BuildDrawings(NestDto dto, Dictionary<int, Program> programs)
+        private static void ReadSubPrograms(Program parent, Stream stream)
+        {
+            using var reader = new StreamReader(stream);
+            var currentId = -1;
+            var lines = new List<string>();
+
+            string line;
+            while ((line = reader.ReadLine()) != null)
+            {
+                var trimmed = line.Trim();
+
+                if (trimmed.StartsWith(":") && int.TryParse(trimmed.Substring(1), out var id))
+                {
+                    // Flush previous sub-program
+                    if (currentId >= 0 && lines.Count > 0)
+                        parent.SubPrograms[currentId] = ParseSubProgram(lines);
+
+                    currentId = id;
+                    lines.Clear();
+                }
+                else if (trimmed == "M99")
+                {
+                    if (currentId >= 0 && lines.Count > 0)
+                        parent.SubPrograms[currentId] = ParseSubProgram(lines);
+
+                    currentId = -1;
+                    lines.Clear();
+                }
+                else
+                {
+                    lines.Add(trimmed);
+                }
+            }
+
+            // Wire up SubProgramCall.Program references
+            foreach (var code in parent.Codes)
+            {
+                if (code is SubProgramCall call && parent.SubPrograms.TryGetValue(call.Id, out var sub))
+                    call.Program = sub;
+            }
+        }
+
+        private static Program ParseSubProgram(List<string> lines)
+        {
+            var text = string.Join("\n", lines);
+            var memStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(text));
+            var reader = new ProgramReader(memStream);
+            return reader.Read();
+        }
+
+        private Dictionary<int, (List<Entity> entities, HashSet<Guid> suppressed)> ReadEntitySets(int count)
+        {
+            var result = new Dictionary<int, (List<Entity>, HashSet<Guid>)>();
+            for (var i = 1; i <= count; i++)
+            {
+                var entry = zipArchive.GetEntry($"entities/entities-{i}");
+                if (entry == null) continue;
+
+                using var entryStream = entry.Open();
+                using var reader = new StreamReader(entryStream);
+                var json = reader.ReadToEnd();
+                var dto = JsonSerializer.Deserialize<EntitySetDto>(json, JsonOptions);
+                result[i] = EntitySerializer.FromDto(dto);
+            }
+            return result;
+        }
+
+        private Dictionary<int, Drawing> BuildDrawings(NestDto dto, Dictionary<int, Program> programs,
+            Dictionary<int, (List<Entity> entities, HashSet<Guid> suppressed)> entitySets)
         {
             var map = new Dictionary<int, Drawing>();
             foreach (var d in dto.Drawings)
@@ -112,6 +189,12 @@ namespace OpenNest.IO
                 if (programs.TryGetValue(d.Id, out var pgm))
                     drawing.Program = pgm;
 
+                if (entitySets.TryGetValue(d.Id, out var entitySet))
+                {
+                    drawing.SourceEntities = entitySet.entities;
+                    drawing.SuppressedEntityIds = entitySet.suppressed;
+                }
+
                 map[d.Id] = drawing;
             }
             return map;

OpenNest.IO/NestWriter.cs

@@ -41,6 +41,7 @@ namespace OpenNest.IO
 
             WriteNestJson(zipArchive);
             WritePrograms(zipArchive);
+            WriteEntities(zipArchive);
             WriteBestFits(zipArchive);
 
             return true;
@@ -307,8 +308,50 @@ namespace OpenNest.IO
                 WriteDrawing(stream, kvp.Value);
 
                 var entry = zipArchive.CreateEntry(name);
-                using var entryStream = entry.Open();
+                using (var entryStream = entry.Open())
-                stream.CopyTo(entryStream);
+                {
+                    stream.CopyTo(entryStream);
+                }
+
+                // Write sub-programs if present
+                if (kvp.Value.Program.SubPrograms.Count > 0)
+                    WriteSubPrograms(zipArchive, kvp.Key, kvp.Value.Program.SubPrograms);
+            }
+        }
+
+        private void WriteSubPrograms(ZipArchive zipArchive, int drawingId, Dictionary<int, Program> subPrograms)
+        {
+            var entry = zipArchive.CreateEntry($"programs/program-{drawingId}-subs");
+            using var entryStream = entry.Open();
+            using var writer = new StreamWriter(entryStream, Encoding.UTF8);
+
+            foreach (var kvp in subPrograms.OrderBy(k => k.Key))
+            {
+                writer.WriteLine($":{kvp.Key}");
+                writer.WriteLine(kvp.Value.Mode == Mode.Absolute ? "G90" : "G91");
+
+                foreach (var code in kvp.Value.Codes)
+                    writer.WriteLine(GetCodeString(code));
+
+                writer.WriteLine("M99");
+            }
+        }
+
+        private void WriteEntities(ZipArchive zipArchive)
+        {
+            foreach (var kvp in drawingDict.OrderBy(k => k.Key))
+            {
+                var drawing = kvp.Value;
+                if (drawing.SourceEntities == null || drawing.SourceEntities.Count == 0)
+                    continue;
+
+                var dto = EntitySerializer.ToDto(drawing.SourceEntities, drawing.SuppressedEntityIds);
+                var json = JsonSerializer.Serialize(dto, JsonOptions);
+
+                var entry = zipArchive.CreateEntry($"entities/entities-{kvp.Key}");
+                using var stream = entry.Open();
+                using var writer = new StreamWriter(stream, Encoding.UTF8);
+                writer.Write(json);
             }
         }
 
@@ -429,7 +472,9 @@ namespace OpenNest.IO
                 case CodeType.SubProgramCall:
                     {
                         var subProgramCall = (SubProgramCall)code;
-                        break;
+                        var x = System.Math.Round(subProgramCall.Offset.X, OutputPrecision).ToString(CoordinateFormat);
+                        var y = System.Math.Round(subProgramCall.Offset.Y, OutputPrecision).ToString(CoordinateFormat);
+                        return $"G65P{subProgramCall.Id}X{x}Y{y}";
                     }
             }
 

OpenNest.IO/ProgramReader.cs

@@ -374,6 +374,8 @@ namespace OpenNest.IO
         {
             var p = 0;
             var r = 0.0;
+            var x = 0.0;
+            var y = 0.0;
 
             while (section == CodeSection.SubProgram)
             {
@@ -395,13 +397,26 @@ namespace OpenNest.IO
                         r = double.Parse(code.Value);
                         break;
 
+                    case 'X':
+                        x = double.Parse(code.Value);
+                        break;
+
+                    case 'Y':
+                        y = double.Parse(code.Value);
+                        break;
+
                     default:
                         section = CodeSection.Unknown;
                         break;
                 }
             }
 
-            program.Codes.Add(new SubProgramCall() { Id = p, Rotation = r });
+            program.Codes.Add(new SubProgramCall
+            {
+                Id = p,
+                Rotation = r,
+                Offset = new Geometry.Vector(x, y)
+            });
         }
 
         private Code GetNextCode()

OpenNest.Mcp/Tools/InputTools.cs

@@ -1,6 +1,4 @@
 using ModelContextProtocol.Server;
-using OpenNest.Converters;
-using OpenNest.Geometry;
 using OpenNest.IO;
 using OpenNest.Shapes;
 using System.ComponentModel;
@@ -96,24 +94,18 @@ namespace OpenNest.Mcp.Tools
             if (!File.Exists(path))
                 return $"Error: file not found: {path}";
 
-            var geometry = Dxf.GetGeometry(path);
+            try
+            {
+                var drawing = CadImporter.ImportDrawing(path, new CadImportOptions { Name = name });
+                _session.Drawings.Add(drawing);
 
-            if (geometry.Count == 0)
+                var bbox = drawing.Program.BoundingBox();
-                return "Error: failed to read DXF file or no geometry found";
+                return $"Imported drawing '{drawing.Name}': bbox={bbox.Width:F2} x {bbox.Length:F2}";
-
+            }
-            var normalized = ShapeProfile.NormalizeEntities(geometry);
+            catch (System.Exception ex)
-            var pgm = ConvertGeometry.ToProgram(normalized);
+            {
-
+                return $"Error: failed to import '{path}': {ex.Message}";
-            if (pgm == null)
+            }
-                return "Error: failed to convert geometry to program";
-
-            var drawingName = name ?? Path.GetFileNameWithoutExtension(path);
-            var drawing = new Drawing(drawingName, pgm);
-            drawing.Color = Drawing.GetNextColor();
-            _session.Drawings.Add(drawing);
-
-            var bbox = pgm.BoundingBox();
-            return $"Imported drawing '{drawingName}': bbox={bbox.Width:F2} x {bbox.Length:F2}";
         }
 
         [McpServerTool(Name = "create_drawing")]

OpenNest.Posts.Cincinnati/CincinnatiPartSubprogramWriter.cs

@@ -1,5 +1,6 @@
 using System.Collections.Generic;
 using System.IO;
+using System.Text;
 using OpenNest.CNC;
 using OpenNest.Geometry;
 
@@ -15,11 +16,16 @@ public sealed class CincinnatiPartSubprogramWriter
 {
     private readonly CincinnatiPostConfig _config;
     private readonly CincinnatiFeatureWriter _featureWriter;
+    private readonly CoordinateFormatter _fmt;
+    private readonly Dictionary<int, int> _holeSubprograms;
 
-    public CincinnatiPartSubprogramWriter(CincinnatiPostConfig config)
+    public CincinnatiPartSubprogramWriter(CincinnatiPostConfig config,
+        Dictionary<int, int> holeSubprograms = null)
     {
         _config = config;
         _featureWriter = new CincinnatiFeatureWriter(config);
+        _fmt = new CoordinateFormatter(config.PostedAccuracy);
+        _holeSubprograms = holeSubprograms;
     }
 
     /// <summary>
@@ -43,6 +49,15 @@ public sealed class CincinnatiPartSubprogramWriter
         for (var i = 0; i < ordered.Count; i++)
         {
             var (codes, isEtch) = ordered[i];
+            var isLastFeature = i == ordered.Count - 1;
+
+            // SubProgramCall features are emitted as M98 hole calls
+            if (codes.Count == 1 && codes[0] is SubProgramCall holeCall)
+            {
+                WriteHoleSubprogramCall(w, holeCall, i, isLastFeature);
+                continue;
+            }
+
             var featureNumber = i == 0
                 ? _config.FeatureLineNumberStart
                 : 1000 + i + 1;
@@ -54,7 +69,7 @@ public sealed class CincinnatiPartSubprogramWriter
                 FeatureNumber = featureNumber,
                 PartName = drawingName,
                 IsFirstFeatureOfPart = false,
-                IsLastFeatureOnSheet = i == ordered.Count - 1,
+                IsLastFeatureOnSheet = isLastFeature,
                 IsSafetyHeadraise = false,
                 IsExteriorFeature = false,
                 IsEtch = isEtch,
@@ -69,6 +84,30 @@ public sealed class CincinnatiPartSubprogramWriter
         w.WriteLine($"M99 (END OF {drawingName})");
     }
 
+    private void WriteHoleSubprogramCall(TextWriter w, SubProgramCall call,
+        int featureIndex, bool isLastFeature)
+    {
+        var postSubNum = _holeSubprograms != null && _holeSubprograms.TryGetValue(call.Id, out var num)
+            ? num : call.Id;
+
+        var featureNumber = featureIndex == 0
+            ? _config.FeatureLineNumberStart
+            : 1000 + featureIndex + 1;
+
+        var sb = new StringBuilder();
+        if (_config.UseLineNumbers)
+            sb.Append($"N{featureNumber} ");
+        sb.Append($"G52 X{_fmt.FormatCoord(call.Offset.X)} Y{_fmt.FormatCoord(call.Offset.Y)}");
+        w.WriteLine(sb.ToString());
+
+        w.WriteLine($"M98 P{postSubNum}");
+
+        w.WriteLine("G52 X0 Y0");
+
+        if (!isLastFeature)
+            w.WriteLine("M47");
+    }
+
     /// <summary>
     /// If the program has no leading rapid, inserts a synthetic rapid at the
     /// last motion endpoint (the contour return point). This ensures the feature
@@ -136,4 +175,61 @@ public sealed class CincinnatiPartSubprogramWriter
 
         return (mapping, entries);
     }
+
+    /// <summary>
+    /// Scans all parts across all plates and builds a nest-level registry of unique
+    /// hole sub-programs. Deduplicates by comparing sub-program code content.
+    /// </summary>
+    internal static (Dictionary<int, int> modelToPostMapping, List<(int subNum, Program program)> entries)
+        BuildHoleRegistry(IEnumerable<Plate> plates, int startNumber)
+    {
+        var mapping = new Dictionary<int, int>();
+        var entries = new List<(int, Program)>();
+        var contentIndex = new Dictionary<string, int>();
+        var nextSubNum = startNumber;
+
+        foreach (var plate in plates)
+        {
+            foreach (var part in plate.Parts)
+            {
+                if (part.BaseDrawing.IsCutOff) continue;
+                foreach (var code in part.Program.Codes)
+                {
+                    if (code is not SubProgramCall call) continue;
+                    if (mapping.ContainsKey(call.Id)) continue;
+
+                    var canonical = ProgramToCanonical(call.Program);
+                    if (contentIndex.TryGetValue(canonical, out var existingNum))
+                    {
+                        mapping[call.Id] = existingNum;
+                    }
+                    else
+                    {
+                        var subNum = nextSubNum++;
+                        mapping[call.Id] = subNum;
+                        contentIndex[canonical] = subNum;
+                        entries.Add((subNum, call.Program));
+                    }
+                }
+            }
+        }
+
+        return (mapping, entries);
+    }
+
+    private static string ProgramToCanonical(Program pgm)
+    {
+        var sb = new StringBuilder();
+        sb.Append(pgm.Mode == Mode.Absolute ? "A" : "I");
+        foreach (var code in pgm.Codes)
+        {
+            if (code is LinearMove lm)
+                sb.Append($"L{lm.EndPoint.X:F6},{lm.EndPoint.Y:F6},{(int)lm.Layer}");
+            else if (code is ArcMove am)
+                sb.Append($"A{am.EndPoint.X:F6},{am.EndPoint.Y:F6},{am.CenterPoint.X:F6},{am.CenterPoint.Y:F6},{(int)am.Rotation},{(int)am.Layer}");
+            else if (code is RapidMove rm)
+                sb.Append($"R{rm.EndPoint.X:F6},{rm.EndPoint.Y:F6}");
+        }
+        return sb.ToString();
+    }
 }

OpenNest.Posts.Cincinnati/CincinnatiPostConfig.cs

@@ -1,5 +1,7 @@
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Linq;
 
 namespace OpenNest.Posts.Cincinnati
 {
@@ -277,6 +279,24 @@ namespace OpenNest.Posts.Cincinnati
         [DisplayName("Etch Libraries")]
         [Description("Gas-to-library mapping for etch operations.")]
         public List<EtchLibraryEntry> EtchLibraries { get; set; } = new();
+
+        [Category("B. Libraries")]
+        [DisplayName("Selected Library")]
+        [Description("Overrides Material/Thickness/Gas auto-resolution. Pick an existing entry from Material Libraries, or leave blank to auto-resolve.")]
+        [TypeConverter(typeof(MaterialLibraryNameConverter))]
+        public string SelectedLibrary { get; set; } = "";
+
+        public string FindBestLibrary(string materialName, double thickness)
+        {
+            if (MaterialLibraries == null || string.IsNullOrEmpty(materialName))
+                return "";
+
+            return MaterialLibraries
+                .Where(e => string.Equals(e.Material, materialName, StringComparison.OrdinalIgnoreCase))
+                .OrderBy(e => System.Math.Abs(e.Thickness - thickness))
+                .Select(e => e.Library)
+                .FirstOrDefault() ?? "";
+        }
     }
 
     public class MaterialLibraryEntry

OpenNest.Posts.Cincinnati/CincinnatiPostProcessor.cs

@@ -9,7 +9,7 @@ using OpenNest.CNC;
 
 namespace OpenNest.Posts.Cincinnati
 {
-    public sealed class CincinnatiPostProcessor : IConfigurablePostProcessor
+    public sealed class CincinnatiPostProcessor : IConfigurablePostProcessor, IPostProcessorNestAware, IMaterialProvidingPostProcessor
     {
         private static readonly JsonSerializerOptions JsonOptions = new()
         {
@@ -25,6 +25,23 @@ namespace OpenNest.Posts.Cincinnati
 
         object IConfigurablePostProcessor.Config => Config;
 
+        public IEnumerable<string> GetMaterialNames()
+        {
+            if (Config?.MaterialLibraries == null)
+                return System.Array.Empty<string>();
+
+            return Config.MaterialLibraries
+                .Select(e => e.Material)
+                .Where(s => !string.IsNullOrWhiteSpace(s));
+        }
+
+        public void PrepareForNest(Nest nest)
+        {
+            var materialName = nest?.Material?.Name ?? "";
+            var thickness = nest?.Thickness ?? 0.0;
+            Config.SelectedLibrary = Config.FindBestLibrary(materialName, thickness);
+        }
+
         public CincinnatiPostProcessor()
         {
             var configPath = GetConfigPath();
@@ -89,9 +106,15 @@ namespace OpenNest.Posts.Cincinnati
             if (Config.UsePartSubprograms)
                 (partSubprograms, subprogramEntries) = CincinnatiPartSubprogramWriter.BuildRegistry(plates, Config.PartSubprogramStart);
 
+            // 5b. Build hole sub-program registry (SubProgramCalls across all parts)
+            var holeStartNumber = Config.PartSubprogramStart
+                + (subprogramEntries?.Count ?? 0);
+            var (holeMapping, holeEntries) = CincinnatiPartSubprogramWriter.BuildHoleRegistry(plates, holeStartNumber);
+
             // 6. Create writers
             var preamble = new CincinnatiPreambleWriter(Config);
-            var sheetWriter = new CincinnatiSheetWriter(Config, vars);
+            var sheetWriter = new CincinnatiSheetWriter(Config, vars,
+                holeMapping.Count > 0 ? holeMapping : null);
 
             // 7. Build material description from nest
             var material = nest.Material;
@@ -122,7 +145,8 @@ namespace OpenNest.Posts.Cincinnati
             // Part sub-programs (if enabled)
             if (subprogramEntries != null)
             {
-                var partSubWriter = new CincinnatiPartSubprogramWriter(Config);
+                var partSubWriter = new CincinnatiPartSubprogramWriter(Config,
+                    holeMapping.Count > 0 ? holeMapping : null);
                 var sheetDiagonal = firstPlate != null
                     ? System.Math.Sqrt(firstPlate.Size.Width * firstPlate.Size.Width
                         + firstPlate.Size.Length * firstPlate.Size.Length)
@@ -135,6 +159,23 @@ namespace OpenNest.Posts.Cincinnati
                 }
             }
 
+            // Hole sub-programs (SubProgramCall definitions)
+            if (holeEntries.Count > 0)
+            {
+                var holeSubWriter = new CincinnatiPartSubprogramWriter(Config);
+                var sheetDiagonal = firstPlate != null
+                    ? System.Math.Sqrt(firstPlate.Size.Width * firstPlate.Size.Width
+                        + firstPlate.Size.Length * firstPlate.Size.Length)
+                    : 100.0;
+
+                foreach (var (subNum, pgm) in holeEntries)
+                {
+                    CincinnatiPartSubprogramWriter.EnsureLeadingRapid(pgm);
+                    holeSubWriter.Write(writer, pgm, "HOLE", subNum,
+                        initialCutLibrary, etchLibrary, sheetDiagonal);
+                }
+            }
+
             writer.Flush();
         }
 

OpenNest.Posts.Cincinnati/CincinnatiSheetWriter.cs

@@ -17,13 +17,16 @@ public sealed class CincinnatiSheetWriter
     private readonly ProgramVariableManager _vars;
     private readonly CoordinateFormatter _fmt;
     private readonly CincinnatiFeatureWriter _featureWriter;
+    private readonly Dictionary<int, int> _holeSubprograms;
 
-    public CincinnatiSheetWriter(CincinnatiPostConfig config, ProgramVariableManager vars)
+    public CincinnatiSheetWriter(CincinnatiPostConfig config, ProgramVariableManager vars,
+        Dictionary<int, int> holeSubprograms = null)
     {
         _config = config;
         _vars = vars;
         _fmt = new CoordinateFormatter(config.PostedAccuracy);
         _featureWriter = new CincinnatiFeatureWriter(config);
+        _holeSubprograms = holeSubprograms;
     }
 
     /// <summary>
@@ -132,11 +135,21 @@ public sealed class CincinnatiSheetWriter
                 for (var f = 0; f < features.Count; f++)
                 {
                     var (codes, isEtch) = features[f];
+                    var isLastFeature = isLastPart && f == features.Count - 1;
+
+                    // SubProgramCall features are emitted as M98 hole calls
+                    if (codes.Count == 1 && codes[0] is SubProgramCall holeCall)
+                    {
+                        WriteHoleSubprogramCall(w, holeCall, featureIndex, isLastFeature);
+                        featureIndex++;
+                        lastPartName = partName;
+                        continue;
+                    }
+
                     var featureNumber = featureIndex == 0
                         ? _config.FeatureLineNumberStart
                         : 1000 + featureIndex + 1;
 
-                    var isLastFeature = isLastPart && f == features.Count - 1;
                     var cutDistance = FeatureUtils.ComputeCutDistance(codes);
 
                     var ctx = new FeatureContext
@@ -204,6 +217,36 @@ public sealed class CincinnatiSheetWriter
             w.WriteLine("M47");
     }
 
+    private void WriteHoleSubprogramCall(TextWriter w, SubProgramCall call, int featureIndex, bool isLastFeature)
+    {
+        var postSubNum = _holeSubprograms != null && _holeSubprograms.TryGetValue(call.Id, out var num)
+            ? num : call.Id;
+
+        var featureNumber = featureIndex == 0
+            ? _config.FeatureLineNumberStart
+            : 1000 + featureIndex + 1;
+
+        // Shift the local origin to the hole center via G52 (manual §1.52).
+        // G52 does not move the nozzle, so the sub-program's first rapid
+        // (the lead-in to the pierce point) takes the tool straight from the
+        // previous feature's end to pierce. The hole sub-program is authored
+        // in hole-local coordinates and resolves to `hole + local` under the
+        // shift. See docs/cincinnati-post-output.md for the full bracket.
+        var sb = new StringBuilder();
+        if (_config.UseLineNumbers)
+            sb.Append($"N{featureNumber} ");
+        sb.Append($"G52 X{_fmt.FormatCoord(call.Offset.X)} Y{_fmt.FormatCoord(call.Offset.Y)}");
+        w.WriteLine(sb.ToString());
+
+        w.WriteLine($"M98 P{postSubNum}");
+
+        // Cancel the local shift (manual §1.52).
+        w.WriteLine("G52 X0 Y0");
+
+        if (!isLastFeature)
+            w.WriteLine("M47");
+    }
+
     private void WritePartsInline(TextWriter w, List<Part> allParts,
         string cutLibrary, string etchLibrary, double sheetDiagonal,
         double plateWidth, double plateLength,
@@ -228,6 +271,14 @@ public sealed class CincinnatiSheetWriter
             var isSafetyHeadraise = partName != lastPartName && lastPartName != "";
             var isLastFeature = i == features.Count - 1;
 
+            // SubProgramCall features are emitted as M98 hole calls
+            if (codes.Count == 1 && codes[0] is SubProgramCall holeCall)
+            {
+                WriteHoleSubprogramCall(w, holeCall, i, isLastFeature);
+                lastPartName = partName;
+                continue;
+            }
+
             var featureNumber = i == 0
                 ? _config.FeatureLineNumberStart
                 : 1000 + i + 1;

OpenNest.Posts.Cincinnati/FeatureUtils.cs

@@ -21,7 +21,16 @@ public static class FeatureUtils
 
         foreach (var code in codes)
         {
-            if (code is RapidMove)
+            if (code is SubProgramCall)
+            {
+                // Flush any pending feature
+                if (current != null)
+                    features.Add(current);
+                // SubProgramCall is its own feature
+                features.Add(new List<ICode> { code });
+                current = null;
+            }
+            else if (code is RapidMove)
             {
                 if (current != null)
                     features.Add(current);

OpenNest.Posts.Cincinnati/MaterialLibraryNameConverter.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+
+namespace OpenNest.Posts.Cincinnati
+{
+    public sealed class MaterialLibraryNameConverter : StringConverter
+    {
+        public override bool GetStandardValuesSupported(ITypeDescriptorContext context) => true;
+
+        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context) => false;
+
+        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
+        {
+            var config = context?.Instance as CincinnatiPostConfig;
+            var names = new List<string> { "" };
+
+            if (config?.MaterialLibraries != null)
+            {
+                names.AddRange(config.MaterialLibraries
+                    .Select(e => e.Library)
+                    .Where(s => !string.IsNullOrWhiteSpace(s))
+                    .Distinct(StringComparer.OrdinalIgnoreCase)
+                    .OrderBy(s => s, StringComparer.OrdinalIgnoreCase));
+            }
+
+            return new StandardValuesCollection(names);
+        }
+    }
+}

OpenNest.Posts.Cincinnati/MaterialLibraryResolver.cs

@@ -10,15 +10,20 @@ public sealed class MaterialLibraryResolver
 
     private readonly List<MaterialLibraryEntry> _materialLibraries;
     private readonly List<EtchLibraryEntry> _etchLibraries;
+    private readonly string _selectedLibrary;
 
     public MaterialLibraryResolver(CincinnatiPostConfig config)
     {
         _materialLibraries = config.MaterialLibraries ?? new List<MaterialLibraryEntry>();
         _etchLibraries = config.EtchLibraries ?? new List<EtchLibraryEntry>();
+        _selectedLibrary = config.SelectedLibrary ?? "";
     }
 
     public string ResolveCutLibrary(string materialName, double thickness, string gas)
     {
+        if (!string.IsNullOrEmpty(_selectedLibrary))
+            return EnsureLibExtension(_selectedLibrary);
+
         var entry = _materialLibraries.FirstOrDefault(e =>
             string.Equals(e.Material, materialName, StringComparison.OrdinalIgnoreCase) &&
             System.Math.Abs(e.Thickness - thickness) <= ThicknessTolerance &&

OpenNest.Posts.Cincinnati/OpenNest.Posts.Cincinnati.csproj

@@ -6,11 +6,19 @@
   <ItemGroup>
     <ProjectReference Include="..\OpenNest.Core\OpenNest.Core.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <None Update="OpenNest.Posts.Cincinnati.json">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
   <Target Name="CopyToPostsDir" AfterTargets="Build">
     <PropertyGroup>
       <PostsDir>..\OpenNest\bin\$(Configuration)\$(TargetFramework)\Posts\</PostsDir>
+      <ConfigJson>$(MSBuildProjectDirectory)\OpenNest.Posts.Cincinnati.json</ConfigJson>
+      <DeployedConfigJson>$(PostsDir)OpenNest.Posts.Cincinnati.json</DeployedConfigJson>
     </PropertyGroup>
     <MakeDir Directories="$(PostsDir)" />
     <Copy SourceFiles="$(TargetPath)" DestinationFolder="$(PostsDir)" SkipUnchangedFiles="true" ContinueOnError="true" />
+    <Copy SourceFiles="$(ConfigJson)" DestinationFolder="$(PostsDir)" SkipUnchangedFiles="true" ContinueOnError="true" Condition="!Exists('$(DeployedConfigJson)')" />
   </Target>
 </Project>

OpenNest.Posts.Cincinnati/OpenNest.Posts.Cincinnati.json

@@ -0,0 +1,163 @@
+{
+  "ConfigurationName": "CL940",
+  "PostedUnits": "Inches",
+  "PostedAccuracy": 4,
+  "UseLineNumbers": true,
+  "FeatureLineNumberStart": 1,
+  "UseSheetSubprograms": true,
+  "SheetSubprogramStart": 101,
+  "UsePartSubprograms": false,
+  "PartSubprogramStart": 200,
+  "VariableDeclarationSubprogram": 100,
+  "CoordModeBetweenParts": "G92",
+  "ProcessParameterMode": "LibraryFile",
+  "DefaultAssistGas": "O2",
+  "DefaultEtchGas": "N2",
+  "UseExactStopMode": false,
+  "UseSpeedGas": false,
+  "UseAntiDive": true,
+  "UseSmartRapids": false,
+  "KerfCompensation": "ControllerSide",
+  "DefaultKerfSide": "Left",
+  "InteriorM47": "Always",
+  "ExteriorM47": "Always",
+  "M47OverrideDistanceThreshold": null,
+  "SafetyHeadraiseDistance": 2000,
+  "PalletExchange": "EndOfSheet",
+  "LeadInFeedratePercent": 0.5,
+  "LeadInArcLine2FeedratePercent": 0.5,
+  "LeadOutFeedratePercent": 0.5,
+  "CircleFeedrateMultiplier": 0.8,
+  "ArcFeedrate": "None",
+  "ArcFeedrateRanges": [
+    { "MaxRadius": 0.125, "FeedratePercent": 0.25, "VariableNumber": 123 },
+    { "MaxRadius": 0.75, "FeedratePercent": 0.5, "VariableNumber": 124 },
+    { "MaxRadius": 4.5, "FeedratePercent": 0.8, "VariableNumber": 125 }
+  ],
+  "UserVariableStart": 200,
+  "SheetWidthVariable": 110,
+  "SheetLengthVariable": 111,
+  "MaterialLibraries": [
+    { "Material": "Aluminum", "Thickness": 0.032, "Gas": "AIR", "Library": "AL032AIR" },
+    { "Material": "Aluminum", "Thickness": 0.032, "Gas": "N2", "Library": "AL032N2" },
+    { "Material": "Aluminum", "Thickness": 0.032, "Gas": "O2", "Library": "AL032O2" },
+    { "Material": "Aluminum", "Thickness": 0.050, "Gas": "AIR", "Library": "AL050AIR" },
+    { "Material": "Aluminum", "Thickness": 0.050, "Gas": "N2", "Library": "AL050N2" },
+    { "Material": "Aluminum", "Thickness": 0.050, "Gas": "O2", "Library": "AL050O2" },
+    { "Material": "Aluminum", "Thickness": 0.063, "Gas": "AIR", "Library": "AL063AIR" },
+    { "Material": "Aluminum", "Thickness": 0.063, "Gas": "N2", "Library": "AL063N2" },
+    { "Material": "Aluminum", "Thickness": 0.063, "Gas": "O2", "Library": "AL063O2" },
+    { "Material": "Aluminum", "Thickness": 0.080, "Gas": "AIR", "Library": "AL080AIR" },
+    { "Material": "Aluminum", "Thickness": 0.080, "Gas": "N2", "Library": "AL080N2" },
+    { "Material": "Aluminum", "Thickness": 0.080, "Gas": "O2", "Library": "AL080O2" },
+    { "Material": "Aluminum", "Thickness": 0.090, "Gas": "AIR", "Library": "AL090AIR" },
+    { "Material": "Aluminum", "Thickness": 0.090, "Gas": "N2", "Library": "AL090N2" },
+    { "Material": "Aluminum", "Thickness": 0.090, "Gas": "O2", "Library": "AL090O2" },
+    { "Material": "Aluminum", "Thickness": 0.100, "Gas": "AIR", "Library": "AL100AIR" },
+    { "Material": "Aluminum", "Thickness": 0.100, "Gas": "N2", "Library": "AL100N2" },
+    { "Material": "Aluminum", "Thickness": 0.100, "Gas": "O2", "Library": "AL100O2" },
+    { "Material": "Aluminum", "Thickness": 0.125, "Gas": "AIR", "Library": "AL125AIR" },
+    { "Material": "Aluminum", "Thickness": 0.125, "Gas": "N2", "Library": "AL125N2" },
+    { "Material": "Aluminum", "Thickness": 0.125, "Gas": "O2", "Library": "AL125O2" },
+    { "Material": "Aluminum", "Thickness": 0.190, "Gas": "AIR", "Library": "AL190AIR" },
+    { "Material": "Aluminum", "Thickness": 0.190, "Gas": "N2", "Library": "AL190N2" },
+    { "Material": "Aluminum", "Thickness": 0.190, "Gas": "O2", "Library": "AL190O2" },
+    { "Material": "Aluminum", "Thickness": 0.250, "Gas": "AIR", "Library": "AL250AIR" },
+    { "Material": "Aluminum", "Thickness": 0.250, "Gas": "N2", "Library": "AL250N2" },
+    { "Material": "Aluminum", "Thickness": 0.250, "Gas": "O2", "Library": "AL250O2" },
+    { "Material": "Aluminum", "Thickness": 0.375, "Gas": "AIR", "Library": "AL375AIR" },
+    { "Material": "Aluminum", "Thickness": 0.375, "Gas": "N2", "Library": "AL375N2" },
+    { "Material": "Aluminum", "Thickness": 0.375, "Gas": "O2", "Library": "AL375O2" },
+    { "Material": "Aluminum", "Thickness": 0.500, "Gas": "AIR", "Library": "AL500AIR" },
+    { "Material": "Aluminum", "Thickness": 0.500, "Gas": "N2", "Library": "AL500N2" },
+    { "Material": "Aluminum", "Thickness": 0.500, "Gas": "O2", "Library": "AL500O2" },
+    { "Material": "Aluminum", "Thickness": 0.625, "Gas": "N2", "Library": "AL625N2" },
+    { "Material": "Aluminum", "Thickness": 0.750, "Gas": "AIR", "Library": "AL750AIR" },
+    { "Material": "Aluminum", "Thickness": 0.750, "Gas": "N2", "Library": "AL750N2" },
+    { "Material": "Aluminum", "Thickness": 0.750, "Gas": "O2", "Library": "AL750O2" },
+    { "Material": "Aluminum", "Thickness": 1.000, "Gas": "AIR", "Library": "AL1000AIR" },
+    { "Material": "Aluminum", "Thickness": 1.000, "Gas": "N2", "Library": "AL1000N2" },
+
+    { "Material": "Galvanized Steel", "Thickness": 0.135, "Gas": "N2", "Library": "GALV135N2" },
+    { "Material": "Galvanized Steel", "Thickness": 0.188, "Gas": "N2", "Library": "GALV188N2" },
+
+    { "Material": "Carbon Steel", "Thickness": 0.036, "Gas": "AIR", "Library": "MS036AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.036, "Gas": "N2", "Library": "MS036N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.048, "Gas": "AIR", "Library": "MS048AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.048, "Gas": "N2", "Library": "MS048N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.060, "Gas": "AIR", "Library": "MS060AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.060, "Gas": "N2", "Library": "MS060N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.075, "Gas": "AIR", "Library": "MS075AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.075, "Gas": "N2", "Library": "MS075N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.075, "Gas": "N2", "Library": "MS075N2FE" },
+    { "Material": "Carbon Steel", "Thickness": 0.090, "Gas": "N2", "Library": "MS090N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.105, "Gas": "AIR", "Library": "MS105AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.105, "Gas": "N2", "Library": "MS105N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.120, "Gas": "AIR", "Library": "MS120AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.120, "Gas": "N2", "Library": "MS120N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.120, "Gas": "N2", "Library": "MS120N2FE" },
+    { "Material": "Carbon Steel", "Thickness": 0.135, "Gas": "AIR", "Library": "MS135AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.135, "Gas": "N2", "Library": "MS135N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.135, "Gas": "N2", "Library": "MS135N2FE" },
+    { "Material": "Carbon Steel", "Thickness": 0.135, "Gas": "N2", "Library": "MS135N2Panel" },
+    { "Material": "Carbon Steel", "Thickness": 0.188, "Gas": "AIR", "Library": "MS188AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.188, "Gas": "N2", "Library": "MS188N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.188, "Gas": "N2", "Library": "MS188N2FLOORPLATE" },
+    { "Material": "Carbon Steel", "Thickness": 0.188, "Gas": "O2", "Library": "MS188O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.250, "Gas": "AIR", "Library": "MS250AIR" },
+    { "Material": "Carbon Steel", "Thickness": 0.250, "Gas": "N2", "Library": "MS250N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.250, "Gas": "N2", "Library": "MS250N2FLOORPLATE" },
+    { "Material": "Carbon Steel", "Thickness": 0.250, "Gas": "O2", "Library": "MS250O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.313, "Gas": "O2", "Library": "MS313O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.375, "Gas": "O2", "Library": "MS375O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.500, "Gas": "N2", "Library": "MS500N2" },
+    { "Material": "Carbon Steel", "Thickness": 0.500, "Gas": "O2", "Library": "MS500O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.625, "Gas": "O2", "Library": "MS625O2" },
+    { "Material": "Carbon Steel", "Thickness": 0.750, "Gas": "O2", "Library": "MS750O2" },
+    { "Material": "Carbon Steel", "Thickness": 1.000, "Gas": "O2", "Library": "MS1000O2" },
+
+    { "Material": "Stainless Steel", "Thickness": 0.036, "Gas": "AIR", "Library": "SS036AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.036, "Gas": "N2", "Library": "SS036N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.048, "Gas": "AIR", "Library": "SS048AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.048, "Gas": "N2", "Library": "SS048N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.060, "Gas": "AIR", "Library": "SS060AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.060, "Gas": "N2", "Library": "SS060N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.075, "Gas": "AIR", "Library": "SS075AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.075, "Gas": "N2", "Library": "SS075N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.075, "Gas": "N2", "Library": "SS075N2FE" },
+    { "Material": "Stainless Steel", "Thickness": 0.105, "Gas": "AIR", "Library": "SS105AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.105, "Gas": "N2", "Library": "SS105N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.105, "Gas": "N2", "Library": "SS105N2FE" },
+    { "Material": "Stainless Steel", "Thickness": 0.120, "Gas": "AIR", "Library": "SS120AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.120, "Gas": "N2", "Library": "SS120N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.120, "Gas": "N2", "Library": "SS120N2FE" },
+    { "Material": "Stainless Steel", "Thickness": 0.135, "Gas": "AIR", "Library": "SS135AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.135, "Gas": "N2", "Library": "SS135N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.135, "Gas": "N2", "Library": "SS135N2FE" },
+    { "Material": "Stainless Steel", "Thickness": 0.188, "Gas": "AIR", "Library": "SS188AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.188, "Gas": "N2", "Library": "SS188N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.250, "Gas": "AIR", "Library": "SS250AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.250, "Gas": "N2", "Library": "SS250N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.313, "Gas": "N2", "Library": "SS313N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.375, "Gas": "AIR", "Library": "SS375AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.375, "Gas": "N2", "Library": "SS375N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.500, "Gas": "AIR", "Library": "SS500AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.500, "Gas": "N2", "Library": "SS500N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.625, "Gas": "N2", "Library": "SS625N2" },
+    { "Material": "Stainless Steel", "Thickness": 0.750, "Gas": "AIR", "Library": "SS750AIR" },
+    { "Material": "Stainless Steel", "Thickness": 0.750, "Gas": "N2", "Library": "SS750N2" },
+    { "Material": "Stainless Steel", "Thickness": 1.000, "Gas": "AIR", "Library": "SS1000AIR" },
+    { "Material": "Stainless Steel", "Thickness": 1.000, "Gas": "N2", "Library": "SS1000N2" },
+
+    { "Material": "Phenolic", "Thickness": 0.0, "Gas": "", "Library": "Phenolic" },
+    { "Material": "Gasket", "Thickness": 0.250, "Gas": "N2", "Library": "GASKET250N2" }
+  ],
+  "EtchLibraries": [
+    { "Gas": "AIR", "Library": "EtchAIR" },
+    { "Gas": "N2", "Library": "EtchN2" },
+    { "Gas": "N2", "Library": "EtchN2_fast" },
+    { "Gas": "N2", "Library": "Etchn2_no_mark_pvc" },
+    { "Gas": "O2", "Library": "EtchO2" },
+    { "Gas": "O2", "Library": "ETCHO2FINE" }
+  ]
+}

OpenNest.Tests/Converters/SubProgramExpansionTests.cs

@@ -0,0 +1,55 @@
+using OpenNest.CNC;
+using OpenNest.Converters;
+using OpenNest.Geometry;
+
+namespace OpenNest.Tests.Converters;
+
+public class SubProgramExpansionTests
+{
+    [Fact]
+    public void ToGeometry_ExpandsSubProgramCall_WithOffset()
+    {
+        // Sub-program: a small line relative to (0,0)
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(0.5, 0));
+
+        // Main program: call sub at offset (10,20)
+        var main = new Program(Mode.Absolute);
+        main.SubPrograms[1] = sub;
+        main.Codes.Add(new SubProgramCall { Id = 1, Program = sub, Offset = new Vector(10, 20) });
+
+        var geometry = ConvertProgram.ToGeometry(main);
+
+        // The sub-program's line should be offset by (10,20)
+        // Sub emits incremental (0.5,0) from current position.
+        // Since offset is (10,20), the line goes from (10,20) to (10.5,20).
+        Assert.True(geometry.Count > 0);
+        var line = geometry.OfType<Line>().FirstOrDefault();
+        Assert.NotNull(line);
+        Assert.Equal(10.5, line.EndPoint.X, 4);
+        Assert.Equal(20, line.EndPoint.Y, 4);
+    }
+
+    [Fact]
+    public void ToGeometry_MultipleSubProgramCalls_DifferentOffsets()
+    {
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(1, 0));
+
+        var main = new Program(Mode.Absolute);
+        main.SubPrograms[1] = sub;
+        main.Codes.Add(new SubProgramCall { Id = 1, Program = sub, Offset = new Vector(0, 0) });
+        main.Codes.Add(new SubProgramCall { Id = 1, Program = sub, Offset = new Vector(5, 5) });
+
+        var geometry = ConvertProgram.ToGeometry(main);
+        var lines = geometry.OfType<Line>().ToList();
+
+        Assert.Equal(2, lines.Count);
+        // First call at (0,0): line from (0,0) to (1,0)
+        Assert.Equal(1, lines[0].EndPoint.X, 4);
+        Assert.Equal(0, lines[0].EndPoint.Y, 4);
+        // Second call at (5,5): line from (5,5) to (6,5)
+        Assert.Equal(6, lines[1].EndPoint.X, 4);
+        Assert.Equal(5, lines[1].EndPoint.Y, 4);
+    }
+}

OpenNest.Tests/CuttingStrategy/HoleSubProgramTests.cs

@@ -0,0 +1,338 @@
+using OpenNest.CNC;
+using OpenNest.CNC.CuttingStrategy;
+using OpenNest.Converters;
+using OpenNest.Geometry;
+using System.Linq;
+
+namespace OpenNest.Tests.CuttingStrategy;
+
+public class HoleSubProgramTests
+{
+    [Fact]
+    public void SubProgramCall_Offset_DefaultsToZero()
+    {
+        var call = new SubProgramCall();
+        Assert.Equal(0, call.Offset.X);
+        Assert.Equal(0, call.Offset.Y);
+    }
+
+    [Fact]
+    public void SubProgramCall_Offset_StoresValue()
+    {
+        var call = new SubProgramCall { Offset = new Vector(1.5, 2.5) };
+        Assert.Equal(1.5, call.Offset.X);
+        Assert.Equal(2.5, call.Offset.Y);
+    }
+
+    [Fact]
+    public void SubProgramCall_Clone_CopiesOffset()
+    {
+        var call = new SubProgramCall { Id = 1, Offset = new Vector(3, 4) };
+        var clone = (SubProgramCall)call.Clone();
+        Assert.Equal(3, clone.Offset.X);
+        Assert.Equal(4, clone.Offset.Y);
+        Assert.Equal(1, clone.Id);
+    }
+
+    [Fact]
+    public void SubProgramCall_ToString_IncludesOffset()
+    {
+        var call = new SubProgramCall { Id = 1000, Offset = new Vector(1.5, 2.5) };
+        var str = call.ToString();
+        Assert.Contains("P1000", str);
+        Assert.Contains("X1.5", str);
+        Assert.Contains("Y2.5", str);
+    }
+
+    [Fact]
+    public void SubProgramCall_ToString_IncludesOffsetAndRotation()
+    {
+        var call = new SubProgramCall { Id = 1000, Offset = new Vector(1.5, 2.5), Rotation = 30 };
+        var str = call.ToString();
+        Assert.Contains("P1000", str);
+        Assert.Contains("X1.5", str);
+        Assert.Contains("Y2.5", str);
+        Assert.Contains("R30", str);
+    }
+
+    [Fact]
+    public void SubProgramCall_ToString_OmitsZeroFields()
+    {
+        var call = new SubProgramCall { Id = 1000 };
+        var str = call.ToString();
+        Assert.Equal("G65 P1000", str);
+    }
+
+    [Fact]
+    public void Program_SubPrograms_EmptyByDefault()
+    {
+        var pgm = new Program();
+        Assert.NotNull(pgm.SubPrograms);
+        Assert.Empty(pgm.SubPrograms);
+    }
+
+    [Fact]
+    public void Program_SubPrograms_StoresAndRetrieves()
+    {
+        var pgm = new Program();
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(0.1, 0.2));
+
+        pgm.SubPrograms[1] = sub;
+
+        Assert.Single(pgm.SubPrograms);
+        Assert.Same(sub, pgm.SubPrograms[1]);
+    }
+
+    [Fact]
+    public void Program_Clone_DeepCopiesSubPrograms()
+    {
+        var pgm = new Program();
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(0.1, 0.2));
+        pgm.SubPrograms[1] = sub;
+
+        var clone = (Program)pgm.Clone();
+
+        Assert.Single(clone.SubPrograms);
+        Assert.NotSame(sub, clone.SubPrograms[1]);
+        Assert.Equal(Mode.Incremental, clone.SubPrograms[1].Mode);
+    }
+
+    [Fact]
+    public void Apply_CircleHole_EmitsSubProgramCall()
+    {
+        // Create a program with a square perimeter and a circle hole at (5, 5) radius 0.5
+        var pgm = new Program(Mode.Absolute);
+        // Square perimeter
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        // Circle hole at (5, 5) radius 0.5
+        pgm.Codes.Add(new RapidMove(5.5, 5));
+        pgm.Codes.Add(new ArcMove(new Vector(5.5, 5), new Vector(5, 5), RotationType.CW));
+
+        var strategy = new ContourCuttingStrategy
+        {
+            Parameters = new CuttingParameters
+            {
+                ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+                ArcCircleLeadOut = new NoLeadOut()
+            }
+        };
+
+        var result = strategy.Apply(pgm, new Vector(10, 10));
+
+        // Should contain at least one SubProgramCall
+        var calls = result.Program.Codes.OfType<SubProgramCall>().ToList();
+        Assert.Single(calls);
+
+        // The call's offset should be approximately at the hole center (5, 5)
+        var call = calls[0];
+        Assert.Equal(5, call.Offset.X, 1);
+        Assert.Equal(5, call.Offset.Y, 1);
+
+        // The parent program should have a sub-program registered
+        Assert.True(result.Program.SubPrograms.ContainsKey(call.Id));
+    }
+
+    [Fact]
+    public void Apply_TwoIdenticalCircles_ShareSubProgram()
+    {
+        // Square perimeter with two identical circle holes at different positions
+        var pgm = new Program(Mode.Absolute);
+        // Square perimeter
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        // Circle 1 at (2, 2) radius 0.5
+        pgm.Codes.Add(new RapidMove(2.5, 2));
+        pgm.Codes.Add(new ArcMove(new Vector(2.5, 2), new Vector(2, 2), RotationType.CW));
+        // Circle 2 at (6, 6) radius 0.5
+        pgm.Codes.Add(new RapidMove(6.5, 6));
+        pgm.Codes.Add(new ArcMove(new Vector(6.5, 6), new Vector(6, 6), RotationType.CW));
+
+        var strategy = new ContourCuttingStrategy
+        {
+            Parameters = new CuttingParameters
+            {
+                RoundLeadInAngles = true,
+                LeadInAngleIncrement = 5.0,
+                ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+                ArcCircleLeadOut = new NoLeadOut()
+            }
+        };
+
+        var result = strategy.Apply(pgm, new Vector(10, 10));
+
+        var calls = result.Program.Codes.OfType<SubProgramCall>().ToList();
+        Assert.Equal(2, calls.Count);
+
+        // Both calls should reference the same sub-program ID (same radius, same quantized angle)
+        Assert.Equal(calls[0].Id, calls[1].Id);
+
+        // But different offsets
+        Assert.NotEqual(calls[0].Offset.X, calls[1].Offset.X);
+    }
+
+    [Fact]
+    public void Apply_HoleCenters_PreservedInGeometry()
+    {
+        // Square perimeter 10x10 with two circle holes at known positions
+        var holeCenter1 = new Vector(3, 3);
+        var holeCenter2 = new Vector(7, 5);
+        var holeRadius = 0.5;
+
+        var pgm = new Program(Mode.Absolute);
+        // Perimeter
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        // Hole 1 at (3, 3)
+        pgm.Codes.Add(new RapidMove(holeCenter1.X + holeRadius, holeCenter1.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter1.X + holeRadius, holeCenter1.Y),
+            holeCenter1, RotationType.CW));
+        // Hole 2 at (7, 5)
+        pgm.Codes.Add(new RapidMove(holeCenter2.X + holeRadius, holeCenter2.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter2.X + holeRadius, holeCenter2.Y),
+            holeCenter2, RotationType.CW));
+
+        var strategy = new ContourCuttingStrategy
+        {
+            Parameters = new CuttingParameters
+            {
+                ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+                ArcCircleLeadOut = new NoLeadOut()
+            }
+        };
+
+        var result = strategy.Apply(pgm, new Vector(10, 10));
+
+        // Convert to geometry — this is what PlateView renders
+        var geometry = ConvertProgram.ToGeometry(result.Program);
+        var circles = geometry.OfType<Circle>().ToList();
+
+        Assert.Equal(2, circles.Count);
+
+        // Circle centers must match the original hole positions
+        var center1 = circles[0].Center;
+        var center2 = circles[1].Center;
+
+        Assert.Equal(holeCenter1.X, center1.X, 2);
+        Assert.Equal(holeCenter1.Y, center1.Y, 2);
+        Assert.Equal(holeCenter2.X, center2.X, 2);
+        Assert.Equal(holeCenter2.Y, center2.Y, 2);
+    }
+
+    [Fact]
+    public void Part_ApplyLeadIns_HolesAndPerimeter_CorrectPositions()
+    {
+        // Build a drawing with a square and two holes
+        var holeCenter1 = new Vector(3, 3);
+        var holeCenter2 = new Vector(7, 5);
+        var holeRadius = 0.5;
+
+        var pgm = new Program(Mode.Absolute);
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        pgm.Codes.Add(new RapidMove(holeCenter1.X + holeRadius, holeCenter1.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter1.X + holeRadius, holeCenter1.Y),
+            holeCenter1, RotationType.CW));
+        pgm.Codes.Add(new RapidMove(holeCenter2.X + holeRadius, holeCenter2.Y));
+        pgm.Codes.Add(new ArcMove(
+            new Vector(holeCenter2.X + holeRadius, holeCenter2.Y),
+            holeCenter2, RotationType.CW));
+
+        var drawing = new Drawing("TestPart") { Program = pgm };
+        var part = new Part(drawing);
+
+        var parameters = new CuttingParameters
+        {
+            RoundLeadInAngles = true,
+            LeadInAngleIncrement = 5.0,
+            ArcCircleLeadIn = new LineLeadIn { Length = 0.125, ApproachAngle = 90 },
+            ArcCircleLeadOut = new NoLeadOut(),
+            ExternalLeadIn = new LineLeadIn { Length = 0.25, ApproachAngle = 90 },
+            ExternalLeadOut = new NoLeadOut()
+        };
+
+        part.ApplyLeadIns(parameters, new Vector(10, 10));
+
+        // Convert to geometry — this is what PlateView renders
+        var geometry = ConvertProgram.ToGeometry(part.Program);
+        var circles = geometry.OfType<Circle>().ToList();
+        var lines = geometry.OfType<Line>().Where(l => l.Layer != SpecialLayers.Rapid).ToList();
+
+        // Hole circles must be at correct positions
+        Assert.Equal(2, circles.Count);
+        Assert.Equal(holeCenter1.X, circles[0].Center.X, 2);
+        Assert.Equal(holeCenter1.Y, circles[0].Center.Y, 2);
+        Assert.Equal(holeCenter2.X, circles[1].Center.X, 2);
+        Assert.Equal(holeCenter2.Y, circles[1].Center.Y, 2);
+        Assert.Equal(holeRadius, circles[0].Radius, 2);
+        Assert.Equal(holeRadius, circles[1].Radius, 2);
+
+        // Perimeter lines must stay within the original 10x10 bounding box.
+        // This catches the mode conversion bug where perimeter gets shifted
+        // by the last hole's position.
+        foreach (var line in lines)
+        {
+            Assert.True(line.StartPoint.X >= -1 && line.StartPoint.X <= 11,
+                $"Perimeter line start X={line.StartPoint.X} is outside the 10x10 part bounds");
+            Assert.True(line.StartPoint.Y >= -1 && line.StartPoint.Y <= 11,
+                $"Perimeter line start Y={line.StartPoint.Y} is outside the 10x10 part bounds");
+            Assert.True(line.EndPoint.X >= -1 && line.EndPoint.X <= 11,
+                $"Perimeter line end X={line.EndPoint.X} is outside the 10x10 part bounds");
+            Assert.True(line.EndPoint.Y >= -1 && line.EndPoint.Y <= 11,
+                $"Perimeter line end Y={line.EndPoint.Y} is outside the 10x10 part bounds");
+        }
+    }
+
+    [Fact]
+    public void Program_BoundingBox_IncludesSubProgramOffset()
+    {
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(1, 0));
+
+        var main = new Program(Mode.Absolute);
+        main.SubPrograms[1] = sub;
+        main.Codes.Add(new SubProgramCall { Id = 1, Program = sub, Offset = new Vector(10, 20) });
+
+        var box = main.BoundingBox();
+
+        // Sub-program line goes from (10,20) to (11,20)
+        Assert.True(box.Right >= 11);
+        Assert.True(box.Top >= 20);
+    }
+
+    [Fact]
+    public void Program_Rotate_RotatesSubProgramCallOffsets()
+    {
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(1, 0));
+
+        var main = new Program(Mode.Absolute);
+        main.SubPrograms[1] = sub;
+        main.Codes.Add(new SubProgramCall { Id = 1, Program = sub, Offset = new Vector(10, 0) });
+
+        // Rotate 90 degrees CCW around origin
+        main.Rotate(System.Math.PI / 2);
+
+        var call = main.Codes.OfType<SubProgramCall>().First();
+        // (10, 0) rotated 90 CCW = (0, 10)
+        Assert.Equal(0, call.Offset.X, 1);
+        Assert.Equal(10, call.Offset.Y, 1);
+    }
+}

OpenNest.Tests/Engine/MultiPlateNesterTests.cs

@@ -229,16 +229,9 @@ public class MultiPlateNesterTests
             MakeItem("big2", 70, 35, 1),
         };
 
-        var result = MultiPlateNester.Nest(
+        var options = new MultiPlateNestOptions { Template = template };
-            items, template,
+
-            plateOptions: null,
+        var result = MultiPlateNester.Nest(items, options);
-            salvageRate: 0.5,
-            sortOrder: PartSortOrder.BoundingBoxArea,
-            minRemnantSize: 12.0,
-            allowPlateCreation: true,
-            existingPlates: null,
-            progress: null,
-            token: CancellationToken.None);
 
         // Each large part should be on its own plate.
         Assert.True(result.Plates.Count >= 2,
@@ -261,16 +254,9 @@ public class MultiPlateNesterTests
             MakeItem("tinyB", 4, 4, 3),
         };
 
-        var result = MultiPlateNester.Nest(
+        var options = new MultiPlateNestOptions { Template = template };
-            items, template,
+
-            plateOptions: null,
+        var result = MultiPlateNester.Nest(items, options);
-            salvageRate: 0.5,
-            sortOrder: PartSortOrder.BoundingBoxArea,
-            minRemnantSize: 12.0,
-            allowPlateCreation: true,
-            existingPlates: null,
-            progress: null,
-            token: CancellationToken.None);
 
         // Both small drawing types should share space — not each on their own plate.
         // With consolidation, they pack into remaining space alongside the big part.
@@ -291,16 +277,13 @@ public class MultiPlateNesterTests
             MakeItem("big2", 70, 35, 1),
         };
 
-        var result = MultiPlateNester.Nest(
+        var options = new MultiPlateNestOptions
-            items, template,
+        {
-            plateOptions: null,
+            Template = template,
-            salvageRate: 0.5,
+            AllowPlateCreation = false,
-            sortOrder: PartSortOrder.BoundingBoxArea,
+        };
-            minRemnantSize: 12.0,
+
-            allowPlateCreation: false,
+        var result = MultiPlateNester.Nest(items, options);
-            existingPlates: null,
-            progress: null,
-            token: CancellationToken.None);
 
         // No existing plates and no plate creation — nothing can be placed.
         Assert.Empty(result.Plates);
@@ -325,16 +308,10 @@ public class MultiPlateNesterTests
             MakeItem("medium", 24, 22, 1),
         };
 
-        var result = MultiPlateNester.Nest(
+        var options = new MultiPlateNestOptions { Template = template };
-            items, template,
+
-            plateOptions: null,
+        var result = MultiPlateNester.Nest(items, options,
-            salvageRate: 0.5,
+            existingPlates: new List<Plate> { existingPlate });
-            sortOrder: PartSortOrder.BoundingBoxArea,
-            minRemnantSize: 12.0,
-            allowPlateCreation: true,
-            existingPlates: new List<Plate> { existingPlate },
-            progress: null,
-            token: CancellationToken.None);
 
         // Part should be placed on the existing plate, not a new one.
         Assert.Single(result.Plates);
@@ -403,16 +380,13 @@ public class MultiPlateNesterTests
         _output.WriteLine($"Plate options: {string.Join(", ", plateOptions.Select(o => $"{o.Width}x{o.Length}"))}");
         _output.WriteLine("");
 
-        var result = MultiPlateNester.Nest(
+        var options = new MultiPlateNestOptions
-            items, template,
+        {
-            plateOptions: plateOptions,
+            Template = template,
-            salvageRate: 0.5,
+            PlateOptions = plateOptions,
-            sortOrder: PartSortOrder.BoundingBoxArea,
+        };
-            minRemnantSize: 12.0,
+
-            allowPlateCreation: true,
+        var result = MultiPlateNester.Nest(items, options);
-            existingPlates: null,
-            progress: null,
-            token: CancellationToken.None);
 
         _output.WriteLine($"=== RESULTS: {result.Plates.Count} plates ===");
 

OpenNest.Tests/Fill/FillLinearCircleTests.cs

@@ -0,0 +1,130 @@
+using OpenNest;
+using OpenNest.CNC;
+using OpenNest.Converters;
+using OpenNest.Engine.Fill;
+using OpenNest.Geometry;
+using OpenNest.Math;
+using Xunit;
+using Xunit.Abstractions;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace OpenNest.Tests.Fill
+{
+    public class FillLinearCircleTests
+    {
+        private readonly ITestOutputHelper _output;
+
+        public FillLinearCircleTests(ITestOutputHelper output) => _output = output;
+
+        private static Drawing MakeCircleDrawing(double radius)
+        {
+            var pgm = new Program();
+            var startPt = new Vector(radius * 2, radius); // rightmost point
+            pgm.Codes.Add(new RapidMove(startPt));
+            pgm.Codes.Add(new ArcMove(startPt, new Vector(radius, radius), RotationType.CCW));
+            return new Drawing("circle", pgm);
+        }
+
+        private static Drawing MakeRingDrawing(double outerRadius, double innerRadius)
+        {
+            var pgm = new Program();
+            // Outer circle (CCW)
+            var outerStart = new Vector(outerRadius * 2, outerRadius);
+            pgm.Codes.Add(new RapidMove(outerStart));
+            pgm.Codes.Add(new ArcMove(outerStart, new Vector(outerRadius, outerRadius), RotationType.CCW));
+            // Inner circle (CW = hole)
+            var innerStart = new Vector(outerRadius + innerRadius, outerRadius);
+            pgm.Codes.Add(new RapidMove(innerStart));
+            pgm.Codes.Add(new ArcMove(innerStart, new Vector(outerRadius, outerRadius), RotationType.CW));
+            return new Drawing("ring", pgm);
+        }
+
+        [Theory]
+        [InlineData(2.0, 0.125)]   // 4" diameter circle, 1/8" spacing
+        [InlineData(1.0, 0.125)]   // 2" diameter circle
+        [InlineData(3.0, 0.0625)]  // 6" diameter circle, 1/16" spacing
+        [InlineData(0.5, 0.25)]    // 1" diameter circle, 1/4" spacing
+        public void CircleFill_OffsetBoundaries_DoNotOverlap(double radius, double spacing)
+        {
+            var drawing = MakeCircleDrawing(radius);
+            var workArea = new Box(0, 0, 48, 48);
+            var engine = new FillLinear(workArea, spacing);
+            var parts = engine.Fill(drawing, 0, NestDirection.Horizontal);
+
+            _output.WriteLine($"Circle R={radius}, spacing={spacing}: {parts.Count} parts");
+
+            AssertNoOffsetOverlap(parts, spacing, radius * 2);
+        }
+
+        [Theory]
+        [InlineData(2.0, 1.5, 0.125)]  // Ring: outer R=2, inner R=1.5
+        [InlineData(1.5, 1.0, 0.125)]  // Ring: outer R=1.5, inner R=1.0
+        public void RingFill_OffsetBoundaries_DoNotOverlap(double outerR, double innerR, double spacing)
+        {
+            var drawing = MakeRingDrawing(outerR, innerR);
+            var workArea = new Box(0, 0, 48, 48);
+            var engine = new FillLinear(workArea, spacing);
+            var parts = engine.Fill(drawing, 0, NestDirection.Horizontal);
+
+            _output.WriteLine($"Ring outerR={outerR}, innerR={innerR}, spacing={spacing}: {parts.Count} parts");
+
+            AssertNoOffsetOverlap(parts, spacing, outerR * 2);
+        }
+
+        private void AssertNoOffsetOverlap(List<Part> parts, double spacing, double expectedDiameter)
+        {
+            if (parts.Count < 2)
+            {
+                _output.WriteLine("  Only 1 part placed, skipping overlap check");
+                return;
+            }
+
+            var halfSpacing = spacing / 2;
+            var radius = expectedDiameter / 2;
+            var minGap = double.MaxValue;
+            var violationCount = 0;
+
+            // For circular parts, the center is at Location + (radius, radius).
+            for (var i = 0; i < parts.Count; i++)
+            {
+                var ci = parts[i].Location + new Vector(radius, radius);
+
+                for (var j = i + 1; j < parts.Count; j++)
+                {
+                    var cj = parts[j].Location + new Vector(radius, radius);
+                    var centerDist = ci.DistanceTo(cj);
+
+                    // Gap between raw circle perimeters
+                    var rawGap = centerDist - expectedDiameter;
+
+                    // Gap between offset circle perimeters (halfSpacing each side)
+                    var offsetGap = centerDist - expectedDiameter - spacing;
+
+                    if (rawGap < minGap)
+                        minGap = rawGap;
+
+                    if (rawGap < spacing - Tolerance.Epsilon)
+                    {
+                        violationCount++;
+                        if (violationCount <= 5)
+                        {
+                            _output.WriteLine($"  SPACING VIOLATION parts[{i}] vs parts[{j}]: " +
+                                $"centerDist={centerDist:F6}, rawGap={rawGap:F6}, offsetGap={offsetGap:F6}, " +
+                                $"expected>={spacing:F4}");
+                        }
+                    }
+                }
+            }
+
+            _output.WriteLine($"  Min gap={minGap:F6}, expected>={spacing:F4}, violations={violationCount}");
+
+            if (violationCount > 0)
+            {
+                var maxDeficit = spacing - minGap;
+                _output.WriteLine($"  Max deficit={maxDeficit:F6}");
+                Assert.Fail($"{violationCount} pairs violate spacing: min gap={minGap:F6}, expected>={spacing}, deficit={maxDeficit:F6}");
+            }
+        }
+    }
+}

OpenNest.Tests/Geometry/SpatialQueryTests.cs

@@ -0,0 +1,349 @@
+using OpenNest.Geometry;
+using OpenNest.Math;
+using System.Collections.Generic;
+
+namespace OpenNest.Tests.Geometry;
+
+public class SpatialQueryTests
+{
+    #region Helpers
+
+    private static List<Entity> MakeSquare(double size)
+    {
+        return new List<Entity>
+        {
+            new Line(0, 0, size, 0),
+            new Line(size, 0, size, size),
+            new Line(size, size, 0, size),
+            new Line(0, size, 0, 0),
+        };
+    }
+
+    private static List<Entity> MakeRoundedRect(double length, double width, double r)
+    {
+        return new List<Entity>
+        {
+            new Line(r, 0, length - r, 0),
+            new Arc(length - r, r, r, Angle.ToRadians(270), Angle.ToRadians(360)),
+            new Line(length, r, length, width - r),
+            new Arc(length - r, width - r, r, Angle.ToRadians(0), Angle.ToRadians(90)),
+            new Line(length - r, width, r, width),
+            new Arc(r, width - r, r, Angle.ToRadians(90), Angle.ToRadians(180)),
+            new Line(0, width - r, 0, r),
+            new Arc(r, r, r, Angle.ToRadians(180), Angle.ToRadians(270)),
+        };
+    }
+
+    private static List<Entity> MakeCircle(double cx, double cy, double radius)
+    {
+        return new List<Entity> { new Circle(cx, cy, radius) };
+    }
+
+    private static List<Entity> Translate(List<Entity> entities, double dx, double dy)
+    {
+        var result = new List<Entity>();
+        foreach (var e in entities)
+        {
+            if (e is Line line)
+                result.Add(new Line(line.pt1.X + dx, line.pt1.Y + dy, line.pt2.X + dx, line.pt2.Y + dy));
+            else if (e is Arc arc)
+                result.Add(new Arc(arc.Center.X + dx, arc.Center.Y + dy, arc.Radius, arc.StartAngle, arc.EndAngle));
+            else if (e is Circle circle)
+                result.Add(new Circle(circle.Center.X + dx, circle.Center.Y + dy, circle.Radius));
+        }
+        return result;
+    }
+
+    #endregion
+
+    #region Circle vs Circle
+
+    [Fact]
+    public void CircleToCircle_Right_ReturnsGap()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Left_ReturnsGap()
+    {
+        var a = MakeCircle(20, 0, 5);
+        var b = MakeCircle(0, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(-1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Up_ReturnsGap()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(0, 20, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, 1));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToCircle_Touching_ReturnsZero()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(10, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void CircleToCircle_NoPath_ReturnsMaxValue()
+    {
+        var a = MakeCircle(0, 0, 3);
+        var b = MakeCircle(0, 20, 3);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void CircleToCircle_PushDirection_Right()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, PushDirection.Right);
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Square vs Square
+
+    [Fact]
+    public void SquareToSquare_Right_ReturnsGap()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 25, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Left_ReturnsGap()
+    {
+        var a = Translate(MakeSquare(10), 25, 0);
+        var b = MakeSquare(10);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(-1, 0));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Down_ReturnsGap()
+    {
+        var a = Translate(MakeSquare(10), 0, 25);
+        var b = MakeSquare(10);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, -1));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void SquareToSquare_Touching_ReturnsZero()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 10, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void SquareToSquare_NoOverlap_ReturnsMaxValue()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 0, 20);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void SquareToSquare_PartialOverlap_Right()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 20, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Rounded Rectangle
+
+    [Fact]
+    public void RoundedRect_Right_ReturnsGap()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 30, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void RoundedRect_Up_ReturnsGap()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 0, 25);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(0, 1));
+
+        Assert.InRange(dist, 14.9, 15.1);
+    }
+
+    [Fact]
+    public void RoundedRect_Touching_ReturnsZero()
+    {
+        var a = MakeRoundedRect(20, 10, 2);
+        var b = Translate(MakeRoundedRect(20, 10, 2), 20, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    [Fact]
+    public void RoundedRect_Diagonal_ReturnsDistance()
+    {
+        var dir = new Vector(1 / System.Math.Sqrt(2), 1 / System.Math.Sqrt(2));
+        var a = MakeRoundedRect(10, 10, 2);
+        var b = Translate(MakeRoundedRect(10, 10, 2), 20, 20);
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, dir);
+
+        Assert.True(dist > 0 && dist < double.MaxValue);
+    }
+
+    #endregion
+
+    #region Circle vs Square
+
+    [Fact]
+    public void CircleToSquare_Right_ReturnsGap()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var square = Translate(MakeSquare(10), 15, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, square, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void SquareToCircle_Right_ReturnsGap()
+    {
+        var square = MakeSquare(10);
+        var circle = MakeCircle(25, 5, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(square, circle, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void CircleToSquare_Touching_ReturnsZero()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var square = Translate(MakeSquare(10), 5, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, square, new Vector(1, 0));
+
+        Assert.InRange(dist, -0.01, 0.01);
+    }
+
+    #endregion
+
+    #region Circle vs Rounded Rectangle
+
+    [Fact]
+    public void CircleToRoundedRect_Right_ReturnsGap()
+    {
+        var circle = MakeCircle(0, 5, 5);
+        var rect = Translate(MakeRoundedRect(20, 10, 2), 15, 0);
+
+        var dist = SpatialQuery.DirectionalDistance(circle, rect, new Vector(1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    [Fact]
+    public void RoundedRectToCircle_Left_ReturnsGap()
+    {
+        var rect = Translate(MakeRoundedRect(20, 10, 2), 15, 0);
+        var circle = MakeCircle(0, 5, 5);
+
+        var dist = SpatialQuery.DirectionalDistance(rect, circle, new Vector(-1, 0));
+
+        Assert.InRange(dist, 9.9, 10.1);
+    }
+
+    #endregion
+
+    #region Edge cases
+
+    [Fact]
+    public void EmptyLists_ReturnsMaxValue()
+    {
+        var a = new List<Entity>();
+        var b = new List<Entity>();
+
+        var dist = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+
+        Assert.Equal(double.MaxValue, dist);
+    }
+
+    [Fact]
+    public void Symmetry_LeftRightReturnSameDistance()
+    {
+        var a = MakeSquare(10);
+        var b = Translate(MakeSquare(10), 25, 0);
+
+        var right = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+        var left = SpatialQuery.DirectionalDistance(b, a, new Vector(-1, 0));
+
+        Assert.InRange(System.Math.Abs(right - left), 0, 0.01);
+    }
+
+    [Fact]
+    public void Symmetry_CirclesLeftRightSame()
+    {
+        var a = MakeCircle(0, 0, 5);
+        var b = MakeCircle(20, 0, 5);
+
+        var right = SpatialQuery.DirectionalDistance(a, b, new Vector(1, 0));
+        var left = SpatialQuery.DirectionalDistance(b, a, new Vector(-1, 0));
+
+        Assert.InRange(System.Math.Abs(right - left), 0, 0.01);
+    }
+
+    #endregion
+}

OpenNest.Tests/IO/CadImporterTests.cs

@@ -0,0 +1,138 @@
+using System.IO;
+using System.Linq;
+using OpenNest.IO;
+using Xunit;
+
+namespace OpenNest.Tests.IO
+{
+    public class CadImporterTests
+    {
+        private static string TestDxf =>
+            Path.Combine("Bending", "TestData", "4526 A14 PT11.dxf");
+
+        [Fact]
+        public void Import_LoadsEntitiesAndDetectsBends()
+        {
+            var result = CadImporter.Import(TestDxf);
+
+            Assert.NotNull(result);
+            Assert.NotEmpty(result.Entities);
+            Assert.NotNull(result.Bends);
+            Assert.NotNull(result.Bounds);
+            Assert.Equal(TestDxf, result.SourcePath);
+            Assert.Equal("4526 A14 PT11", result.Name);
+        }
+
+        [Fact]
+        public void Import_WhenDetectBendsFalse_ReturnsEmptyBends()
+        {
+            var result = CadImporter.Import(TestDxf, new CadImportOptions { DetectBends = false });
+
+            Assert.Empty(result.Bends);
+        }
+
+        [Fact]
+        public void Import_WhenNameOverrideProvided_UsesOverride()
+        {
+            var result = CadImporter.Import(TestDxf, new CadImportOptions { Name = "custom" });
+
+            Assert.Equal("custom", result.Name);
+        }
+
+        [Fact]
+        public void Import_WhenNamedDetectorDoesNotExist_ReturnsEmptyBends()
+        {
+            // Exercises the named-detector branch: when BendDetectorName doesn't
+            // match any registered detector, bends should be an empty list
+            // (not a crash, and no fall-through to auto-detect).
+            var result = CadImporter.Import(TestDxf,
+                new CadImportOptions { BendDetectorName = "__nonexistent__" });
+
+            Assert.Empty(result.Bends);
+        }
+
+        [Fact]
+        public void BuildDrawing_ProducesDrawingWithProgramAndMetadata()
+        {
+            var result = CadImporter.Import(TestDxf);
+
+            var drawing = CadImporter.BuildDrawing(
+                result,
+                result.Entities,
+                result.Bends,
+                quantity: 5,
+                customer: "ACME",
+                editedProgram: null);
+
+            Assert.NotNull(drawing);
+            Assert.Equal("4526 A14 PT11", drawing.Name);
+            Assert.Equal("ACME", drawing.Customer);
+            Assert.Equal(5, drawing.Quantity.Required);
+            Assert.Equal(TestDxf, drawing.Source.Path);
+            Assert.NotNull(drawing.Program);
+            Assert.NotEmpty(drawing.Program.Codes);
+            Assert.NotNull(drawing.SourceEntities);
+            Assert.NotEmpty(drawing.SourceEntities);
+        }
+
+        [Fact]
+        public void BuildDrawing_ExtractsFirstRapidAsSourceOffset()
+        {
+            var result = CadImporter.Import(TestDxf);
+
+            var drawing = CadImporter.BuildDrawing(result, result.Entities, result.Bends,
+                quantity: 1, customer: null, editedProgram: null);
+
+            Assert.NotNull(drawing.Source.Offset);
+            // After offset extraction, the program's first rapid must start at origin.
+            var firstRapid = (OpenNest.CNC.RapidMove)drawing.Program.Codes[0];
+            Assert.Equal(0, firstRapid.EndPoint.X, 6);
+            Assert.Equal(0, firstRapid.EndPoint.Y, 6);
+        }
+
+        [Fact]
+        public void BuildDrawing_WhenEntityHidden_TracksSuppressedId()
+        {
+            var result = CadImporter.Import(TestDxf);
+            // Suppress the first non-bend-source entity
+            var bendSources = result.Bends
+                .Where(b => b.SourceEntity != null)
+                .Select(b => b.SourceEntity)
+                .ToHashSet();
+            var hidden = result.Entities.First(e => !bendSources.Contains(e));
+            hidden.IsVisible = false;
+
+            var drawing = CadImporter.BuildDrawing(result, result.Entities, result.Bends,
+                quantity: 1, customer: null, editedProgram: null);
+
+            Assert.Contains(hidden.Id, drawing.SuppressedEntityIds);
+        }
+
+        [Fact]
+        public void BuildDrawing_WhenEditedProgramProvided_UsesEditedProgram()
+        {
+            var result = CadImporter.Import(TestDxf);
+            var edited = new OpenNest.CNC.Program();
+            edited.MoveTo(new OpenNest.Geometry.Vector(0, 0));
+
+            var drawing = CadImporter.BuildDrawing(result, result.Entities, result.Bends,
+                quantity: 1, customer: null, editedProgram: edited);
+
+            Assert.Same(edited, drawing.Program);
+        }
+
+        [Fact]
+        public void ImportDrawing_ComposesImportAndBuild()
+        {
+            var drawing = CadImporter.ImportDrawing(TestDxf,
+                new CadImportOptions { Quantity = 3, Customer = "ACME" });
+
+            Assert.NotNull(drawing);
+            Assert.Equal("4526 A14 PT11", drawing.Name);
+            Assert.Equal(3, drawing.Quantity.Required);
+            Assert.Equal("ACME", drawing.Customer);
+            Assert.NotNull(drawing.Program);
+            Assert.NotNull(drawing.SourceEntities);
+        }
+    }
+}

OpenNest.Tests/IO/SubProgramSerializationTests.cs

@@ -0,0 +1,75 @@
+using OpenNest.CNC;
+using OpenNest.Geometry;
+using OpenNest.IO;
+
+namespace OpenNest.Tests.IO;
+
+public class SubProgramSerializationTests
+{
+    [Fact]
+    public void NestWriter_WritesSubProgramCall_WithOffset()
+    {
+        var nest = CreateNestWithHoleSubProgram();
+
+        using var stream = new MemoryStream();
+        var writer = new NestWriter(nest);
+        writer.Write(stream);
+        stream.Position = 0;
+
+        var reader = new NestReader(stream);
+        var loaded = reader.Read();
+
+        var drawing = loaded.Drawings.First();
+        var calls = drawing.Program.Codes.OfType<SubProgramCall>().ToList();
+        Assert.Single(calls);
+        Assert.Equal(5, calls[0].Offset.X, 1);
+        Assert.Equal(5, calls[0].Offset.Y, 1);
+    }
+
+    [Fact]
+    public void NestWriter_WritesSubPrograms_AndRestoresOnLoad()
+    {
+        var nest = CreateNestWithHoleSubProgram();
+
+        using var stream = new MemoryStream();
+        var writer = new NestWriter(nest);
+        writer.Write(stream);
+        stream.Position = 0;
+
+        var reader = new NestReader(stream);
+        var loaded = reader.Read();
+
+        var drawing = loaded.Drawings.First();
+        Assert.True(drawing.Program.SubPrograms.Count > 0);
+
+        var call = drawing.Program.Codes.OfType<SubProgramCall>().First();
+        Assert.True(drawing.Program.SubPrograms.ContainsKey(call.Id));
+    }
+
+    private static Nest CreateNestWithHoleSubProgram()
+    {
+        var sub = new Program(Mode.Incremental);
+        sub.Codes.Add(new LinearMove(0.1, 0) { Layer = LayerType.Leadin });
+        sub.Codes.Add(new ArcMove(new Vector(0, 0), new Vector(-0.5, 0), RotationType.CW));
+
+        var pgm = new Program(Mode.Absolute);
+        pgm.SubPrograms[42] = sub;
+        pgm.Codes.Add(new SubProgramCall { Id = 42, Program = sub, Offset = new Vector(5, 5) });
+        // Add perimeter so the drawing has non-zero geometry
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(10, 0));
+        pgm.Codes.Add(new LinearMove(10, 10));
+        pgm.Codes.Add(new LinearMove(0, 10));
+        pgm.Codes.Add(new LinearMove(0, 0));
+
+        var drawing = new Drawing("TestPart") { Program = pgm };
+        var nest = new Nest();
+        nest.Drawings.Add(drawing);
+
+        var plate = new Plate { Size = new Size(48, 96) };
+        plate.Parts.Add(new Part(drawing));
+        nest.Plates.Add(plate);
+
+        return nest;
+    }
+}

OpenNest.Training/Program.cs

@@ -1,8 +1,8 @@
 using OpenNest;
 using OpenNest.Engine.BestFit;
 using OpenNest.Engine.ML;
-using OpenNest.Geometry;
 using OpenNest.Gpu;
+using OpenNest.Geometry;
 using OpenNest.IO;
 using OpenNest.Training;
 using System;
@@ -128,17 +128,26 @@ int RunDataCollection(string dir, string dbPath, string saveDir, double s, strin
                 continue;
             }
 
-            var entities = Dxf.GetGeometry(file);
+            Drawing drawing;
-            if (entities.Count == 0)
+            try
+            {
+                drawing = CadImporter.ImportDrawing(file,
+                    new CadImportOptions { DetectBends = false, Name = Path.GetFileName(file) });
+            }
+            catch (System.Exception ex)
+            {
+                Console.WriteLine($" - SKIP ({ex.Message})");
+                skippedGeometry++;
+                continue;
+            }
+
+            if (drawing.Program == null || drawing.Program.Codes.Count == 0)
             {
                 Console.WriteLine(" - SKIP (no geometry)");
                 skippedGeometry++;
                 continue;
             }
 
-            var drawing = new Drawing(Path.GetFileName(file));
-            var normalized = ShapeProfile.NormalizeEntities(entities);
-            drawing.Program = OpenNest.Converters.ConvertGeometry.ToProgram(normalized);
             drawing.UpdateArea();
             drawing.Color = PartColors[colorIndex % PartColors.Length];
             colorIndex++;

OpenNest/ArchUnits.cs

@@ -0,0 +1,84 @@
+using OpenNest.IO.Bom;
+using System;
+using System.Drawing;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Windows.Forms;
+
+namespace OpenNest
+{
+    public static class ArchUnits
+    {
+        private static readonly Regex UnitRegex =
+            new Regex("^(?<Feet>\\d+\\.?\\d*\\s*')?\\s*(?<Inches>\\d+\\.?\\d*\\s*\")?$");
+
+        public static double ParseToInches(string input)
+        {
+            if (string.IsNullOrWhiteSpace(input))
+                return 0;
+
+            var sb = new StringBuilder(input.Trim().ToLower());
+
+            sb.Replace("ft", "'");
+            sb.Replace("feet", "'");
+            sb.Replace("foot", "'");
+            sb.Replace("inches", "\"");
+            sb.Replace("inch", "\"");
+            sb.Replace("in", "\"");
+
+            input = Fraction.ReplaceFractionsWithDecimals(sb.ToString());
+
+            var match = UnitRegex.Match(input);
+
+            if (!match.Success)
+            {
+                if (!input.Contains("'") && !input.Contains("\""))
+                {
+                    if (double.TryParse(input.Trim(), out var plainInches))
+                        return System.Math.Round(plainInches, 8);
+                }
+
+                throw new FormatException("Input is not in a valid format.");
+            }
+
+            var feet = match.Groups["Feet"];
+            var inches = match.Groups["Inches"];
+            var totalInches = 0.0;
+
+            if (feet.Success)
+            {
+                var x = double.Parse(feet.Value.Remove(feet.Length - 1));
+                totalInches += x * 12;
+            }
+
+            if (inches.Success)
+            {
+                var x = double.Parse(inches.Value.Remove(inches.Length - 1));
+                totalInches += x;
+            }
+
+            return System.Math.Round(totalInches, 8);
+        }
+
+        public static double GetLengthInches(TextBox tb)
+        {
+            try
+            {
+                if (double.TryParse(tb.Text, out var d))
+                {
+                    tb.ForeColor = SystemColors.WindowText;
+                    return d;
+                }
+
+                var x = ParseToInches(tb.Text);
+                tb.ForeColor = SystemColors.WindowText;
+                return x;
+            }
+            catch
+            {
+                tb.ForeColor = Color.Red;
+                return double.NaN;
+            }
+        }
+    }
+}

OpenNest/Controls/ActionManager.cs

@@ -0,0 +1,118 @@
+using System;
+using System.ComponentModel;
+using Action = OpenNest.Actions.Action;
+
+namespace OpenNest.Controls
+{
+    internal class ActionManager
+    {
+        private readonly PlateView view;
+        private Action currentAction;
+        private Action previousAction;
+
+        public ActionManager(PlateView view)
+        {
+            this.view = view;
+        }
+
+        public Action CurrentAction => currentAction;
+
+        public void SetAction(Type type)
+        {
+            var action = Activator.CreateInstance(type, view) as Action;
+            if (action == null)
+                return;
+
+            if (currentAction != null)
+            {
+                if (type == typeof(Actions.ActionSelect) && !(currentAction is Actions.ActionSelect))
+                    previousAction = currentAction;
+                else
+                    previousAction = null;
+
+                currentAction.CancelAction();
+                currentAction.DisconnectEvents();
+                currentAction = null;
+            }
+
+            currentAction = action;
+            view.Status = GetDisplayName(type);
+        }
+
+        public void SetAction(Type type, params object[] args)
+        {
+            if (currentAction != null)
+            {
+                previousAction = null;
+                currentAction.CancelAction();
+                currentAction.DisconnectEvents();
+                currentAction = null;
+            }
+
+            Array.Resize(ref args, args.Length + 1);
+            for (var i = args.Length - 2; i >= 0; i--)
+                args[i + 1] = args[i];
+            args[0] = view;
+
+            var action = Activator.CreateInstance(type, args) as Action;
+            if (action == null)
+                return;
+
+            currentAction = action;
+            view.Status = GetDisplayName(type);
+        }
+
+        public void ProcessEscapeKey()
+        {
+            if (currentAction.IsBusy())
+                currentAction.CancelAction();
+            else if (currentAction is Actions.ActionSelect && previousAction != null)
+                RestorePreviousAction();
+            else
+                view.SetAction(typeof(Actions.ActionSelect));
+        }
+
+        public void RestorePreviousAction()
+        {
+            var action = previousAction;
+            previousAction = null;
+
+            currentAction.CancelAction();
+            currentAction.DisconnectEvents();
+
+            action.ConnectEvents();
+            currentAction = action;
+
+            view.Status = GetDisplayName(action.GetType());
+        }
+
+        public void OnPlateChanged()
+        {
+            if (currentAction == null || !currentAction.SurvivesPlateChange)
+                view.SetAction(typeof(Actions.ActionSelect));
+            else
+                currentAction.OnPlateChanged();
+        }
+
+        public void Cleanup()
+        {
+            if (currentAction != null)
+            {
+                currentAction.CancelAction();
+                currentAction.DisconnectEvents();
+                currentAction = null;
+            }
+        }
+
+        private string GetDisplayName(Type type)
+        {
+            var attributes = type.GetCustomAttributes(true);
+            foreach (var attr in attributes)
+            {
+                if (attr is DisplayNameAttribute displayNameAttr)
+                    return displayNameAttr.DisplayName;
+            }
+            return type.Name;
+        }
+    }
+}

OpenNest/Controls/CutDirectionArrows.cs

@@ -9,6 +9,12 @@ namespace OpenNest.Controls
     {
         public static void DrawProgram(Graphics g, DrawControl view, Program pgm, ref Vector pos,
             Pen pen, double spacing, float arrowSize)
+        {
+            DrawProgram(g, view, pgm, pos, ref pos, pen, spacing, arrowSize);
+        }
+
+        private static void DrawProgram(Graphics g, DrawControl view, Program pgm, Vector basePos, ref Vector pos,
+            Pen pen, double spacing, float arrowSize)
         {
             for (var i = 0; i < pgm.Length; ++i)
             {
@@ -18,7 +24,11 @@ namespace OpenNest.Controls
                 {
                     var subpgm = (SubProgramCall)code;
                     if (subpgm.Program != null)
-                        DrawProgram(g, view, subpgm.Program, ref pos, pen, spacing, arrowSize);
+                    {
+                        var holeBase = basePos + subpgm.Offset;
+                        pos = holeBase;
+                        DrawProgram(g, view, subpgm.Program, holeBase, ref pos, pen, spacing, arrowSize);
+                    }
                     continue;
                 }
 
@@ -26,7 +36,7 @@ namespace OpenNest.Controls
 
                 var endpt = pgm.Mode == Mode.Incremental
                     ? motion.EndPoint + pos
-                    : motion.EndPoint;
+                    : motion.EndPoint + basePos;
 
                 if (code.Type == CodeType.LinearMove)
                 {
@@ -41,7 +51,7 @@ namespace OpenNest.Controls
                     {
                         var center = pgm.Mode == Mode.Incremental
                             ? arc.CenterPoint + pos
-                            : arc.CenterPoint;
+                            : arc.CenterPoint + basePos;
                         DrawArcArrows(g, view, pos, endpt, center, arc.Rotation, pen, spacing, arrowSize);
                     }
                 }

OpenNest/Controls/CutOffHandler.cs

@@ -0,0 +1,81 @@
+using OpenNest.CNC;
+using OpenNest.Geometry;
+using System.Collections.Generic;
+
+namespace OpenNest.Controls
+{
+    internal class CutOffHandler
+    {
+        private readonly PlateView view;
+        private Dictionary<Part, Geometry.Entity> dragPerimeterCache;
+
+        public CutOffHandler(PlateView view)
+        {
+            this.view = view;
+        }
+
+        public bool IsDragging { get; private set; }
+
+        public CutOff TryStartDrag(Vector point, double tolerance)
+        {
+            var hitCutOff = GetCutOffAtPoint(point, tolerance);
+            if (hitCutOff == null)
+                return null;
+
+            IsDragging = true;
+            dragPerimeterCache = Plate.BuildPerimeterCache(view.Plate);
+            return hitCutOff;
+        }
+
+        public void UpdateDrag(Vector currentPoint, CutOff cutOff)
+        {
+            if (!IsDragging || cutOff == null)
+                return;
+
+            if (cutOff.Axis == CutOffAxis.Vertical)
+                cutOff.Position = new Vector(currentPoint.X, cutOff.Position.Y);
+            else
+                cutOff.Position = new Vector(cutOff.Position.X, currentPoint.Y);
+
+            cutOff.Regenerate(view.Plate, view.CutOffSettings, dragPerimeterCache);
+            view.Invalidate();
+        }
+
+        public void EndDrag()
+        {
+            if (!IsDragging)
+                return;
+
+            IsDragging = false;
+            dragPerimeterCache = null;
+            view.Plate.RegenerateCutOffs(view.CutOffSettings);
+            view.Invalidate();
+        }
+
+        public CutOff GetCutOffAtPoint(Vector point, double tolerance)
+        {
+            if (view.Plate?.CutOffs == null)
+                return null;
+
+            foreach (var cutoff in view.Plate.CutOffs)
+            {
+                var program = cutoff.Drawing?.Program;
+                if (program == null)
+                    continue;
+
+                for (var i = 0; i < program.Codes.Count - 1; i += 2)
+                {
+                    if (program.Codes[i] is RapidMove rapid &&
+                        program.Codes[i + 1] is LinearMove linear)
+                    {
+                        var line = new Line(rapid.EndPoint, linear.EndPoint);
+                        if (line.ClosestPointTo(point).DistanceTo(point) <= tolerance)
+                            return cutoff;
+                    }
+                }
+            }
+
+            return null;
+        }
+    }
+}

OpenNest/Controls/CuttingPanel.cs

@@ -11,7 +11,7 @@ namespace OpenNest.Controls
             { "None", "Line", "Arc", "Line + Arc", "Clean Hole", "Line + Line" };
 
         private static readonly string[] LeadOutTypes =
-            { "None", "Line", "Arc", "Microtab" };
+            { "None", "Line", "Arc" };
 
         private readonly TabControl tabControl;
         private readonly ComboBox cboExternalLeadIn, cboExternalLeadOut;
@@ -28,6 +28,9 @@ namespace OpenNest.Controls
         private readonly NumericUpDown nudAutoTabMax;
         private readonly NumericUpDown nudPierceClearance;
 
+        private readonly CheckBox chkRoundLeadInAngles;
+        private readonly NumericUpDown nudLeadInAngleIncrement;
+
         private readonly Button btnAutoAssign;
 
         private bool suppressEvents;
@@ -162,7 +165,7 @@ namespace OpenNest.Controls
             {
                 HeaderText = "Pierce",
                 Dock = DockStyle.Top,
-                ExpandedHeight = 60,
+                ExpandedHeight = 90,
                 IsExpanded = true
             };
 
@@ -176,6 +179,34 @@ namespace OpenNest.Controls
             nudPierceClearance = CreateNumeric(130, 3, 0.0625, 0.0625);
             piercePanel.ContentPanel.Controls.Add(nudPierceClearance);
 
+            chkRoundLeadInAngles = new CheckBox
+            {
+                Text = "Round Lead-In Angles",
+                Location = new Point(12, 32),
+                AutoSize = true
+            };
+            chkRoundLeadInAngles.CheckedChanged += (s, e) =>
+            {
+                nudLeadInAngleIncrement.Enabled = chkRoundLeadInAngles.Checked;
+                OnParametersChanged();
+            };
+            piercePanel.ContentPanel.Controls.Add(chkRoundLeadInAngles);
+
+            piercePanel.ContentPanel.Controls.Add(new Label
+            {
+                Text = "Increment:",
+                Location = new Point(175, 34),
+                AutoSize = true
+            });
+
+            nudLeadInAngleIncrement = CreateNumeric(245, 31, 5, 1);
+            nudLeadInAngleIncrement.DecimalPlaces = 0;
+            nudLeadInAngleIncrement.Minimum = 1;
+            nudLeadInAngleIncrement.Maximum = 90;
+            nudLeadInAngleIncrement.Enabled = false;
+            nudLeadInAngleIncrement.ValueChanged += (s, e) => OnParametersChanged();
+            piercePanel.ContentPanel.Controls.Add(nudLeadInAngleIncrement);
+
             // Auto-Assign button — wrapped in a panel for Dock.Top with padding
             btnAutoAssign = new Button
             {
@@ -218,6 +249,8 @@ namespace OpenNest.Controls
                 TabsEnabled = chkTabsEnabled.Checked,
                 TabConfig = new NormalTab { Size = (double)nudTabWidth.Value },
                 PierceClearance = (double)nudPierceClearance.Value,
+                RoundLeadInAngles = chkRoundLeadInAngles.Checked,
+                LeadInAngleIncrement = (double)nudLeadInAngleIncrement.Value,
                 AutoTabMinSize = (double)nudAutoTabMin.Value,
                 AutoTabMaxSize = (double)nudAutoTabMax.Value
             };
@@ -238,6 +271,9 @@ namespace OpenNest.Controls
             if (p.TabConfig != null)
                 nudTabWidth.Value = (decimal)p.TabConfig.Size;
             nudPierceClearance.Value = (decimal)p.PierceClearance;
+            chkRoundLeadInAngles.Checked = p.RoundLeadInAngles;
+            nudLeadInAngleIncrement.Value = (decimal)p.LeadInAngleIncrement;
+            nudLeadInAngleIncrement.Enabled = p.RoundLeadInAngles;
             nudAutoTabMin.Value = (decimal)p.AutoTabMinSize;
             nudAutoTabMax.Value = (decimal)p.AutoTabMaxSize;
 
@@ -424,9 +460,6 @@ namespace OpenNest.Controls
                 case 2:
                     AddNumericField(panel, "Radius:", 0.25, ref y, "Radius");
                     break;
-                case 3:
-                    AddNumericField(panel, "Gap Size:", 0.06, ref y, "GapSize");
-                    break;
             }
         }
 
@@ -513,10 +546,6 @@ namespace OpenNest.Controls
                     combo.SelectedIndex = 2;
                     SetParam(panel, "Radius", arc.Radius);
                     break;
-                case MicrotabLeadOut microtab:
-                    combo.SelectedIndex = 3;
-                    SetParam(panel, "GapSize", microtab.GapSize);
-                    break;
                 default:
                     combo.SelectedIndex = 0;
                     break;
@@ -572,10 +601,6 @@ namespace OpenNest.Controls
                 {
                     Radius = GetParam(panel, "Radius", 0.25)
                 },
-                3 => new MicrotabLeadOut
-                {
-                    GapSize = GetParam(panel, "GapSize", 0.06)
-                },
                 _ => new NoLeadOut()
             };
         }

OpenNest/Controls/DrawControl.cs

@@ -29,7 +29,7 @@ namespace OpenNest.Controls
         {
             ViewScale = 1.0f;
             ViewScaleMin = 0.3f;
-            ViewScaleMax = 3000;
+            ViewScaleMax = 10000;
             origin = new PointF(100, 100);
         }
 

OpenNest/Controls/DrawingListBox.cs

@@ -8,16 +8,14 @@ namespace OpenNest.Controls
 
     public class DrawingListBox : ListBox
     {
+        private const int WM_ERASEBKGND = 0x0014;
+
         private readonly Size imageSize;
         private readonly Font nameFont;
         private Point lastClickLocation;
 
         public DrawingListBox()
         {
-            SetStyle(
-                ControlStyles.AllPaintingInWmPaint |
-                ControlStyles.OptimizedDoubleBuffer, true);
-
             DrawMode = DrawMode.OwnerDrawFixed;
             ItemHeight = 85;
 
@@ -149,6 +147,30 @@ namespace OpenNest.Controls
             base.OnMouseDown(e);
             lastClickLocation = e.Location;
         }
+
+        protected override void WndProc(ref Message m)
+        {
+            if (m.Msg == WM_ERASEBKGND)
+            {
+                var itemBottom = 0;
+
+                if (Items.Count > 0)
+                {
+                    var lastVisible = System.Math.Min(TopIndex + (ClientSize.Height / ItemHeight), Items.Count - 1);
+                    itemBottom = GetItemRectangle(lastVisible).Bottom;
+                }
+
+                if (itemBottom < ClientSize.Height)
+                {
+                    using var g = Graphics.FromHdc(m.WParam);
+                    g.FillRectangle(Brushes.White, 0, itemBottom, ClientSize.Width, ClientSize.Height - itemBottom);
+                }
+
+                m.Result = (IntPtr)1;
+                return;
+            }
+            base.WndProc(ref m);
+        }
     }
 
     public static class PointExtensions

OpenNest/Controls/FileListControl.cs

@@ -19,6 +19,7 @@ namespace OpenNest.Controls
         public List<Entity> Entities { get; set; } = new();
         public List<Entity> OriginalEntities { get; set; }
         public List<Bend> Bends { get; set; } = new();
+        public HashSet<Guid> SuppressedEntityIds { get; set; }
         public Box Bounds { get; set; }
         public int EntityCount { get; set; }
     }

OpenNest/Controls/FilterPanel.cs

@@ -154,7 +154,10 @@ namespace OpenNest.Controls
                 Font = new Font("Segoe UI", 9f)
             };
             list.ItemCheck += (s, e) =>
-                BeginInvoke((Action)(() => FilterChanged?.Invoke(this, EventArgs.Empty)));
+            {
+                if (IsHandleCreated)
+                    BeginInvoke((Action)(() => FilterChanged?.Invoke(this, EventArgs.Empty)));
+            };
             return list;
         }
 
@@ -167,10 +170,11 @@ namespace OpenNest.Controls
             layersList.Items.Clear();
             var layers = entities
                 .Where(e => e.Layer != null)
-                .Select(e => e.Layer.Name)
+                .Select(e => e.Layer)
-                .Distinct();
+                .GroupBy(l => l.Name)
+                .Select(g => g.First());
             foreach (var layer in layers)
-                layersList.Items.Add(layer, true); // checked = visible
+                layersList.Items.Add(layer.Name, layer.IsVisible);
 
             layersPanel.HeaderText = $"Layers ({layersList.Items.Count})";
 
@@ -188,10 +192,10 @@ namespace OpenNest.Controls
             // Line Types
             lineTypesList.Items.Clear();
             var lineTypes = entities
-                .Select(e => e.LineTypeName ?? "Continuous")
+                .GroupBy(e => e.LineTypeName ?? "Continuous")
-                .Distinct();
+                .Select(g => new { Name = g.Key, Visible = g.Any(e => e.IsVisible) });
             foreach (var lt in lineTypes)
-                lineTypesList.Items.Add(lt, true); // checked = visible
+                lineTypesList.Items.Add(lt.Name, lt.Visible);
 
             lineTypesPanel.HeaderText = $"Line Types ({lineTypesList.Items.Count})";
 

OpenNest/Controls/PlateRenderer.cs

@@ -168,7 +168,7 @@ namespace OpenNest.Controls
                 if (program == null || program.Codes.Count == 0)
                     continue;
 
-                var activePen = cutoff == view.SelectedCutOff ? selectedPen : pen;
+                var activePen = view.Selection.SelectedCutOffs.Contains(cutoff) ? selectedPen : pen;
 
                 for (var i = 0; i < program.Codes.Count - 1; i += 2)
                 {
@@ -395,8 +395,8 @@ namespace OpenNest.Controls
                 var piercePoint = GetFirstPiercePoint(pgm, part.Location);
                 DrawLine(g, pos, piercePoint, view.ColorScheme.RapidPen);
 
-                pos = part.Location;
+                pos = piercePoint;
-                DrawRapids(g, pgm, ref pos, skipFirstRapid: true);
+                DrawRapids(g, pgm, part.Location, ref pos, skipFirstRapid: true);
             }
         }
 
@@ -404,17 +404,18 @@ namespace OpenNest.Controls
         {
             for (var i = 0; i < pgm.Length; i++)
             {
+                if (pgm[i] is SubProgramCall call && call.Program != null)
+                    return GetFirstPiercePoint(call.Program, partLocation + call.Offset);
+
                 if (pgm[i] is Motion motion)
                 {
-                    if (pgm.Mode == Mode.Incremental)
+                    return motion.EndPoint + partLocation;
-                        return motion.EndPoint + partLocation;
-                    return motion.EndPoint;
                 }
             }
             return partLocation;
         }
 
-        private void DrawRapids(Graphics g, Program pgm, ref Vector pos, bool skipFirstRapid = false)
+        private void DrawRapids(Graphics g, Program pgm, Vector basePos, ref Vector pos, bool skipFirstRapid = false)
         {
             var firstRapidSkipped = false;
 
@@ -422,49 +423,49 @@ namespace OpenNest.Controls
             {
                 var code = pgm[i];
 
-                if (code.Type == CodeType.SubProgramCall)
+                if (code is SubProgramCall { Program: { } program } call)
                 {
-                    var subpgm = (SubProgramCall)code;
+                    // A SubProgramCall is a coordinate-frame shift, not a physical
-                    var program = subpgm.Program;
+                    // rapid to the hole center. The Cincinnati post emits it as a
+                    // G52 bracket, so the physical rapid is the sub-program's first
+                    // motion, which goes straight from here to the lead-in pierce.
+                    // Look ahead for that pierce point and draw the direct rapid,
+                    // then recurse with skipFirstRapid so the sub doesn't also draw
+                    // its first rapid on top. See docs/cincinnati-post-output.md.
+                    var holeBase = basePos + call.Offset;
+                    var firstPierce = GetFirstPiercePoint(program, holeBase);
 
-                    if (program != null)
+                    if (ShouldDrawRapid(skipFirstRapid, ref firstRapidSkipped))
-                        DrawRapids(g, program, ref pos);
+                        DrawLine(g, pos, firstPierce, view.ColorScheme.RapidPen);
+
+                    var subPos = holeBase;
+                    DrawRapids(g, program, holeBase, ref subPos, skipFirstRapid: true);
+                    pos = subPos;
                 }
-                else
+                else if (code is Motion motion)
                 {
-                    var motion = code as Motion;
+                    var endpt = pgm.Mode == Mode.Incremental
+                        ? motion.EndPoint + pos
+                        : motion.EndPoint;
 
-                    if (motion != null)
+                    if (code.Type == CodeType.RapidMove && ShouldDrawRapid(skipFirstRapid, ref firstRapidSkipped))
-                    {
+                        DrawLine(g, pos, endpt, view.ColorScheme.RapidPen);
-                        if (pgm.Mode == Mode.Incremental)
-                        {
-                            var endpt = motion.EndPoint + pos;
 
-                            if (code.Type == CodeType.RapidMove)
+                    pos = endpt;
-                            {
-                                if (skipFirstRapid && !firstRapidSkipped)
-                                    firstRapidSkipped = true;
-                                else
-                                    DrawLine(g, pos, endpt, view.ColorScheme.RapidPen);
-                            }
-                            pos = endpt;
-                        }
-                        else
-                        {
-                            if (code.Type == CodeType.RapidMove)
-                            {
-                                if (skipFirstRapid && !firstRapidSkipped)
-                                    firstRapidSkipped = true;
-                                else
-                                    DrawLine(g, pos, motion.EndPoint, view.ColorScheme.RapidPen);
-                            }
-                            pos = motion.EndPoint;
-                        }
-                    }
                 }
             }
         }
 
+        private static bool ShouldDrawRapid(bool skipFirstRapid, ref bool firstRapidSkipped)
+        {
+            if (skipFirstRapid && !firstRapidSkipped)
+            {
+                firstRapidSkipped = true;
+                return false;
+            }
+            return true;
+        }
+
         private void DrawAllPiercePoints(Graphics g)
         {
             using var brush = new SolidBrush(Color.Red);
@@ -475,11 +476,11 @@ namespace OpenNest.Controls
                 var part = view.Plate.Parts[i];
                 var pgm = part.Program;
                 var pos = part.Location;
-                DrawProgramPiercePoints(g, pgm, ref pos, brush, pen);
+                DrawProgramPiercePoints(g, pgm, part.Location, ref pos, brush, pen);
             }
         }
 
-        private void DrawProgramPiercePoints(Graphics g, Program pgm, ref Vector pos, Brush brush, Pen pen)
+        private void DrawProgramPiercePoints(Graphics g, Program pgm, Vector basePos, ref Vector pos, Brush brush, Pen pen)
         {
             for (var i = 0; i < pgm.Length; ++i)
             {
@@ -489,7 +490,11 @@ namespace OpenNest.Controls
                 {
                     var subpgm = (SubProgramCall)code;
                     if (subpgm.Program != null)
-                        DrawProgramPiercePoints(g, subpgm.Program, ref pos, brush, pen);
+                    {
+                        var holeBase = basePos + subpgm.Offset;
+                        pos = holeBase;
+                        DrawProgramPiercePoints(g, subpgm.Program, holeBase, ref pos, brush, pen);
+                    }
                 }
                 else
                 {
@@ -498,7 +503,7 @@ namespace OpenNest.Controls
 
                     var endpt = pgm.Mode == Mode.Incremental
                         ? motion.EndPoint + pos
-                        : motion.EndPoint;
+                        : motion.EndPoint + basePos;
 
                     if (code.Type == CodeType.RapidMove)
                     {

OpenNest/Controls/PlateView.cs

@@ -1,5 +1,4 @@
 using OpenNest.Actions;
-using OpenNest.CNC;
 using OpenNest.Collections;
 using OpenNest.Engine.Fill;
 using OpenNest.Forms;
@@ -8,7 +7,6 @@ using OpenNest.Math;
 using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
-using System.ComponentModel;
 using System.Diagnostics;
 using System.Drawing;
 using System.Drawing.Drawing2D;
@@ -16,31 +14,30 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
-using Action = OpenNest.Actions.Action;
 using Timer = System.Timers.Timer;
 
 namespace OpenNest.Controls
 {
     public class PlateView : DrawControl
     {
-        private readonly Font programIdFont;
         private readonly Timer redrawTimer;
 
         private string status;
         private Plate plate;
-        private Action currentAction;
+        private ActionManager actionManager;
-        private Action previousAction;
         private CutOffSettings cutOffSettings = new CutOffSettings();
-        private CutOff selectedCutOff;
+        private SelectionManager selection;
-        private bool draggingCutOff;
+        private CutOffHandler cutOffHandler;
-        private Dictionary<Part, Geometry.Entity> dragPerimeterCache;
+        private PreviewManager previewManager;
         protected List<LayoutPart> parts;
-        private List<LayoutPart> stationaryParts = new List<LayoutPart>();
-        private List<LayoutPart> activeParts = new List<LayoutPart>();
         private Point middleMouseDownPoint;
         private Box activeWorkArea;
         private List<Box> debugRemnants;
         private PlateRenderer renderer;
+        private LayoutPart hoveredPart;
+        private Point hoverPoint;
+        private bool showTooltip;
+        private Timer hoverTimer;
 
         public Box ActiveWorkArea
         {
@@ -64,13 +61,23 @@ namespace OpenNest.Controls
 
         public List<int> DebugRemnantPriorities { get; set; }
 
-        public List<LayoutPart> SelectedParts;
+        public List<LayoutPart> SelectedParts => selection.SelectedParts;
-        public ReadOnlyCollection<LayoutPart> Parts;
+        public ReadOnlyCollection<LayoutPart> Parts => new ReadOnlyCollection<LayoutPart>(parts);
+
+        internal SelectionManager Selection => selection;
+        internal CutOffHandler CutOffs => cutOffHandler;
+        internal ActionManager Actions => actionManager;
+        internal PreviewManager Previews => previewManager;
 
         public event EventHandler<ItemAddedEventArgs<Part>> PartAdded;
         public event EventHandler<ItemRemovedEventArgs<Part>> PartRemoved;
         public event EventHandler StatusChanged;
-        public event EventHandler SelectionChanged;
+
+        public event EventHandler SelectionChanged
+        {
+            add => selection.SelectionChanged += value;
+            remove => selection.SelectionChanged -= value;
+        }
 
         public PlateView()
             : this(ColorScheme.Default)
@@ -80,11 +87,11 @@ namespace OpenNest.Controls
         public PlateView(ColorScheme colorScheme)
         {
             Plate = new Plate(60, 120);
-            programIdFont = new Font(DefaultFont, FontStyle.Bold | FontStyle.Underline);
             origin = new PointF();
             parts = new List<LayoutPart>();
-            Parts = new ReadOnlyCollection<LayoutPart>(parts);
+            selection = new SelectionManager(this);
-            SelectedParts = new List<LayoutPart>();
+            cutOffHandler = new CutOffHandler(this);
+            previewManager = new PreviewManager(this);
 
             redrawTimer = new Timer()
             {
@@ -94,6 +101,9 @@ namespace OpenNest.Controls
             };
             redrawTimer.Elapsed += redrawTimer_Elapsed;
 
+            hoverTimer = new Timer() { AutoReset = false, Interval = 1000 };
+            hoverTimer.Elapsed += hoverTimer_Elapsed;
+
             SetStyle(
                 ControlStyles.AllPaintingInWmPaint |
                 ControlStyles.OptimizedDoubleBuffer |
@@ -115,7 +125,8 @@ namespace OpenNest.Controls
             DrawOffset = false;
             FillParts = true;
             renderer = new PlateRenderer(this);
-            SetAction(typeof(ActionSelect));
+            actionManager = new ActionManager(this);
+            actionManager.SetAction(typeof(ActionSelect));
 
             UpdateMatrix();
         }
@@ -148,14 +159,9 @@ namespace OpenNest.Controls
 
         internal List<LayoutPart> LayoutParts => parts;
 
-        internal IReadOnlyList<LayoutPart> PreviewParts =>
+        internal IReadOnlyList<LayoutPart> PreviewParts => previewManager.PreviewParts;
-            activeParts.Count > 0 ? activeParts : stationaryParts;
+        internal Brush PreviewBrush => previewManager.PreviewBrush;
-
+        internal Pen PreviewPen => previewManager.PreviewPen;
-        internal Brush PreviewBrush =>
-            activeParts.Count > 0 ? ColorScheme.ActivePreviewPartBrush : ColorScheme.PreviewPartBrush;
-
-        internal Pen PreviewPen =>
-            activeParts.Count > 0 ? ColorScheme.ActivePreviewPartPen : ColorScheme.PreviewPartPen;
 
         internal RectangleF GetViewBounds() =>
             new RectangleF(-origin.X, -origin.Y, Width, Height);
@@ -173,16 +179,6 @@ namespace OpenNest.Controls
             }
         }
 
-        public CutOff SelectedCutOff
-        {
-            get => selectedCutOff;
-            set
-            {
-                selectedCutOff = value;
-                Invalidate();
-            }
-        }
-
         public double RotateIncrementAngle { get; set; }
 
         public double OffsetIncrementDistance { get; set; }
@@ -200,9 +196,8 @@ namespace OpenNest.Controls
                 plate.PartAdded -= plate_PartAdded;
                 plate.PartRemoved -= plate_PartRemoved;
                 parts.Clear();
-                stationaryParts.Clear();
+                previewManager.Clear();
-                activeParts.Clear();
+                selection.Clear();
-                SelectedParts.Clear();
             }
 
             plate = p;
@@ -212,10 +207,7 @@ namespace OpenNest.Controls
             foreach (var part in plate.Parts)
                 parts.Add(LayoutPart.Create(part, this));
 
-            if (currentAction == null || !currentAction.SurvivesPlateChange)
+            actionManager?.OnPlateChanged();
-                SetAction(typeof(ActionSelect));
-            else
-                currentAction.OnPlateChanged();
         }
 
         public string Status
@@ -233,7 +225,6 @@ namespace OpenNest.Controls
         protected override void OnMouseEnter(EventArgs e)
         {
             base.OnMouseEnter(e);
-            if (!Focused) Focus();
         }
 
         protected override void OnDragEnter(DragEventArgs drgevent)
@@ -257,22 +248,25 @@ namespace OpenNest.Controls
 
         protected override void OnMouseDown(MouseEventArgs e)
         {
+            if (!Focused) Focus();
+
             if (e.Button == MouseButtons.Middle)
                 middleMouseDownPoint = e.Location;
 
-            if (e.Button == MouseButtons.Left && currentAction is ActionSelect)
+            if (e.Button == MouseButtons.Left && actionManager.CurrentAction is ActionSelect)
             {
-                var hitCutOff = GetCutOffAtPoint(CurrentPoint, 5.0 / ViewScale);
+                var hitCutOff = cutOffHandler.TryStartDrag(CurrentPoint, 5.0 / ViewScale);
                 if (hitCutOff != null)
                 {
-                    SelectedCutOff = hitCutOff;
+                    selection.DeselectParts();
-                    draggingCutOff = true;
+                    selection.SelectedCutOffs.Clear();
-                    dragPerimeterCache = Plate.BuildPerimeterCache(Plate);
+                    selection.SelectedCutOffs.Add(hitCutOff);
+                    Invalidate();
                     return;
                 }
                 else
                 {
-                    SelectedCutOff = null;
+                    selection.DeselectCutOffs();
                 }
             }
 
@@ -288,17 +282,14 @@ namespace OpenNest.Controls
 
                 if (dx * dx + dy * dy < 25)
                 {
-                    RotateSelectedParts(Angle.ToRadians(90));
+                    selection.RotateSelectedParts(Angle.ToRadians(90));
                     Invalidate();
                 }
             }
 
-            if (draggingCutOff && selectedCutOff != null)
+            if (cutOffHandler.IsDragging && selection.SelectedCutOffs.Count > 0)
             {
-                draggingCutOff = false;
+                cutOffHandler.EndDrag();
-                dragPerimeterCache = null;
-                Plate.RegenerateCutOffs(cutOffSettings);
-                Invalidate();
                 return;
             }
 
@@ -319,7 +310,7 @@ namespace OpenNest.Controls
 
                 var angle = Angle.ToRadians((e.Delta > 0 ? -increment : increment) * multiplier);
 
-                RotateSelectedParts(angle);
+                selection.RotateSelectedParts(angle);
             }
             else
             {
@@ -358,18 +349,30 @@ namespace OpenNest.Controls
 
             lastPoint = e.Location;
 
-            if (draggingCutOff && selectedCutOff != null)
+            if (cutOffHandler.IsDragging && selection.SelectedCutOffs.Count > 0)
             {
-                if (selectedCutOff.Axis == CutOffAxis.Vertical)
+                cutOffHandler.UpdateDrag(CurrentPoint, selection.SelectedCutOffs[0]);
-                    selectedCutOff.Position = new Vector(CurrentPoint.X, selectedCutOff.Position.Y);
-                else
-                    selectedCutOff.Position = new Vector(selectedCutOff.Position.X, CurrentPoint.Y);
-
-                selectedCutOff.Regenerate(Plate, cutOffSettings, dragPerimeterCache);
-                Invalidate();
                 return;
             }
 
+            if (e.Button == MouseButtons.None && actionManager.CurrentAction is ActionSelect)
+            {
+                hoverPoint = e.Location;
+                showTooltip = false;
+                hoverTimer.Stop();
+                hoverTimer.Start();
+
+                if (hoveredPart != null)
+                    Invalidate();
+            }
+            else if (hoveredPart != null || showTooltip)
+            {
+                hoveredPart = null;
+                hoverTimer.Stop();
+                showTooltip = false;
+                Invalidate();
+            }
+
             base.OnMouseMove(e);
         }
 
@@ -386,17 +389,7 @@ namespace OpenNest.Controls
             switch (e.KeyCode)
             {
                 case Keys.Delete:
-                    if (selectedCutOff != null)
+                    selection.DeleteSelected();
-                    {
-                        Plate.CutOffs.Remove(selectedCutOff);
-                        selectedCutOff = null;
-                        Plate.RegenerateCutOffs(cutOffSettings);
-                        Invalidate();
-                    }
-                    else
-                    {
-                        RemoveSelectedParts();
-                    }
                     break;
 
                 case Keys.F:
@@ -412,15 +405,7 @@ namespace OpenNest.Controls
             }
         }
 
-        public void ProcessEscapeKey()
+        public void ProcessEscapeKey() => actionManager.ProcessEscapeKey();
-        {
-            if (currentAction.IsBusy())
-                currentAction.CancelAction();
-            else if (currentAction is ActionSelect && previousAction != null)
-                RestorePreviousAction();
-            else
-                SetAction(typeof(ActionSelect));
-        }
 
         protected override bool ProcessDialogKey(Keys keyData)
         {
@@ -440,22 +425,22 @@ namespace OpenNest.Controls
 
                 case Keys.X:
                 case Keys.Shift | Keys.Left:
-                    PushSelected(PushDirection.Left);
+                    selection.PushSelected(PushDirection.Left);
                     break;
 
                 case Keys.Shift | Keys.X:
                 case Keys.Shift | Keys.Right:
-                    PushSelected(PushDirection.Right);
+                    selection.PushSelected(PushDirection.Right);
                     break;
 
                 case Keys.Shift | Keys.Y:
                 case Keys.Shift | Keys.Up:
-                    PushSelected(PushDirection.Up);
+                    selection.PushSelected(PushDirection.Up);
                     break;
 
                 case Keys.Y:
                 case Keys.Shift | Keys.Down:
-                    PushSelected(PushDirection.Down);
+                    selection.PushSelected(PushDirection.Down);
                     break;
 
                 case Keys.Right:
@@ -496,229 +481,53 @@ namespace OpenNest.Controls
             renderer.DrawDebugRemnants(e.Graphics);
 
             base.OnPaint(e);
+
+            if (hoveredPart != null && showTooltip)
+            {
+                e.Graphics.ResetTransform();
+                var text = hoveredPart.BasePart.BaseDrawing.Name;
+                var size = e.Graphics.MeasureString(text, Font);
+                var x = hoverPoint.X + 16f;
+                var y = hoverPoint.Y - size.Height - 6f;
+
+                if (x + size.Width + 8 > ClientSize.Width)
+                    x = hoverPoint.X - size.Width - 8;
+                if (y < 0)
+                    y = hoverPoint.Y + 20;
+
+                var rect = new RectangleF(x, y, size.Width + 6, size.Height + 4);
+                using (var bgBrush = new SolidBrush(Color.FromArgb(230, Color.White)))
+                    e.Graphics.FillRectangle(bgBrush, rect);
+                e.Graphics.DrawRectangle(Pens.DimGray, rect.X, rect.Y, rect.Width, rect.Height);
+                e.Graphics.DrawString(text, Font, Brushes.Black, x + 3, y + 2);
+            }
         }
 
         protected override void OnHandleDestroyed(EventArgs e)
         {
             base.OnHandleDestroyed(e);
-
+            actionManager.Cleanup();
-            if (currentAction != null)
-            {
-                currentAction.CancelAction();
-                currentAction.DisconnectEvents();
-                currentAction = null;
-            }
         }
 
         public override void Refresh()
         {
             parts.ForEach(p => p.Update(this));
-            stationaryParts.ForEach(p => p.Update(this));
+            previewManager.Update();
-            activeParts.ForEach(p => p.Update(this));
             Invalidate();
         }
 
-        public CutOff GetCutOffAtPoint(Vector point, double tolerance)
+        public CutOff GetCutOffAtPoint(Vector point, double tolerance) => cutOffHandler.GetCutOffAtPoint(point, tolerance);
-        {
-            if (Plate?.CutOffs == null)
-                return null;
 
-            foreach (var cutoff in Plate.CutOffs)
+        public LayoutPart GetPartAtControlPoint(Point pt) => selection.GetPartAtControlPoint(pt);
-            {
+        public LayoutPart GetPartAtGraphPoint(PointF pt) => selection.GetPartAtGraphPoint(pt);
-                var program = cutoff.Drawing?.Program;
+        public LayoutPart GetPartAtPoint(Vector pt) => selection.GetPartAtPoint(pt);
-                if (program == null)
+        public IList<LayoutPart> GetPartsFromWindow(RectangleF rect, SelectionType selectionType) => selection.GetPartsFromWindow(rect, selectionType);
-                    continue;
 
-                for (var i = 0; i < program.Codes.Count - 1; i += 2)
+        public void SetAction(Type type) => actionManager.SetAction(type);
-                {
+        public void SetAction(Type type, params object[] args) => actionManager.SetAction(type, args);
-                    if (program.Codes[i] is RapidMove rapid &&
-                        program.Codes[i + 1] is LinearMove linear)
-                    {
-                        var line = new Geometry.Line(rapid.EndPoint, linear.EndPoint);
-                        if (line.ClosestPointTo(point).DistanceTo(point) <= tolerance)
-                            return cutoff;
-                    }
-                }
-            }
 
-            return null;
+        public void AlignSelected(AlignType alignType) => selection.AlignSelected(alignType);
-        }
+        public void AlignSelected(AlignType alignType, LayoutPart fixedPart) => selection.AlignSelected(alignType, fixedPart);
-
-        public LayoutPart GetPartAtControlPoint(Point pt)
-        {
-            var pt2 = PointControlToGraph(pt);
-            return GetPartAtGraphPoint(pt2);
-        }
-
-        public LayoutPart GetPartAtGraphPoint(PointF pt)
-        {
-            for (int i = parts.Count - 1; i >= 0; --i)
-            {
-                if (parts[i].Path.IsVisible(pt))
-                    return parts[i];
-            }
-
-            return null;
-        }
-
-        public LayoutPart GetPartAtPoint(Vector pt)
-        {
-            var pt2 = PointWorldToGraph(pt);
-            return GetPartAtGraphPoint(pt2);
-        }
-
-        public IList<LayoutPart> GetPartsFromWindow(RectangleF rect, SelectionType selectionType)
-        {
-            var list = new List<LayoutPart>();
-
-            if (selectionType == SelectionType.Intersect)
-            {
-                for (int i = 0; i < parts.Count; ++i)
-                {
-                    var part = parts[i];
-                    var path = part.Path;
-                    var region = new Region(path);
-
-                    if (region.IsVisible(rect))
-                        list.Add(part);
-
-                    region.Dispose();
-                }
-            }
-            else
-            {
-                for (int i = 0; i < parts.Count; ++i)
-                {
-                    var part = parts[i];
-                    var path = part.Path;
-                    var bounds = path.GetBounds();
-
-                    if (rect.Contains(bounds))
-                        list.Add(part);
-                }
-            }
-
-            return list;
-        }
-
-        public void SetAction(Type type)
-        {
-            var action = Activator.CreateInstance(type, this) as Action;
-
-            if (action == null)
-                return;
-
-            if (currentAction != null)
-            {
-                if (type == typeof(ActionSelect) && !(currentAction is ActionSelect))
-                    previousAction = currentAction;
-                else
-                    previousAction = null;
-
-                currentAction.CancelAction();
-                currentAction.DisconnectEvents();
-                currentAction = null;
-            }
-
-            currentAction = action;
-
-            Status = GetDisplayName(type);
-        }
-
-        public void SetAction(Type type, params object[] args)
-        {
-            if (currentAction != null)
-            {
-                previousAction = null;
-                currentAction.CancelAction();
-                currentAction.DisconnectEvents();
-                currentAction = null;
-            }
-
-            Array.Resize(ref args, args.Length + 1);
-
-            // shift all elements to the right
-            for (int i = args.Length - 2; i >= 0; i--)
-                args[i + 1] = args[i];
-
-            // set the first argument to this.
-            args[0] = this;
-
-            var action = Activator.CreateInstance(type, args) as Action;
-
-            if (action == null)
-                return;
-
-            currentAction = action;
-
-            Status = GetDisplayName(type);
-        }
-
-        private void RestorePreviousAction()
-        {
-            var action = previousAction;
-            previousAction = null;
-
-            currentAction.CancelAction();
-            currentAction.DisconnectEvents();
-
-            action.ConnectEvents();
-            currentAction = action;
-
-            Status = GetDisplayName(action.GetType());
-        }
-
-        public void AlignSelected(AlignType alignType)
-        {
-            if (SelectedParts.Count == 0)
-                return;
-
-            AlignSelected(alignType, SelectedParts[0]);
-        }
-
-        public void AlignSelected(AlignType alignType, LayoutPart fixedPart)
-        {
-            switch (alignType)
-            {
-                case AlignType.Bottom:
-                    Align.Bottom(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.Horizontally:
-                    Align.Horizontally(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.Left:
-                    Align.Left(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.Right:
-                    Align.Right(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.Top:
-                    Align.Top(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.Vertically:
-                    Align.Vertically(fixedPart.BasePart, SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.EvenlySpaceHorizontally:
-                    Align.EvenlyDistributeHorizontally(SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                case AlignType.EvenlySpaceVertically:
-                    Align.EvenlyDistributeVertically(SelectedParts.Select(p => p.BasePart).ToList());
-                    break;
-
-                default:
-                    return;
-            }
-
-            SelectedParts.ForEach(p => p.IsDirty = true);
-            Invalidate();
-        }
 
         public void AddPartFromDrawing(Drawing dwg, Vector location)
         {
@@ -731,51 +540,10 @@ namespace OpenNest.Controls
             Plate.Parts.Add(part);
         }
 
-        public void SetStationaryParts(List<Part> parts)
+        public void SetStationaryParts(List<Part> parts) => previewManager.SetStationaryParts(parts);
-        {
+        public void SetActiveParts(List<Part> parts) => previewManager.SetActiveParts(parts);
-            stationaryParts.Clear();
+        public void ClearPreviewParts() => previewManager.ClearPreviewParts();
-            activeParts.Clear();
+        public void AcceptPreviewParts(List<Part> parts) => previewManager.AcceptPreviewParts(parts);
-
-            if (parts != null)
-            {
-                foreach (var part in parts)
-                    stationaryParts.Add(LayoutPart.Create(part, this));
-            }
-
-            Invalidate();
-        }
-
-        public void SetActiveParts(List<Part> parts)
-        {
-            activeParts.Clear();
-
-            if (parts != null)
-            {
-                foreach (var part in parts)
-                    activeParts.Add(LayoutPart.Create(part, this));
-            }
-
-            Invalidate();
-        }
-
-        public void ClearPreviewParts()
-        {
-            stationaryParts.Clear();
-            activeParts.Clear();
-            Invalidate();
-        }
-
-        public void AcceptPreviewParts(List<Part> parts)
-        {
-            if (parts != null)
-            {
-                foreach (var part in parts)
-                    Plate.Parts.Add(part);
-            }
-
-            stationaryParts.Clear();
-            activeParts.Clear();
-        }
 
         public async void FillWithProgress(List<Part> groupParts, Box workArea)
         {
@@ -848,19 +616,41 @@ namespace OpenNest.Controls
             }
         }
 
-        public void RemoveSelectedParts()
+        public void RemoveSelectedParts() => selection.RemoveSelectedParts();
-        {
-            foreach (var part in SelectedParts)
-                Plate.Parts.Remove(part.BasePart);
-
-            DeselectAll();
-            Invalidate();
-        }
 
 
         private void redrawTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
         {
-            Invalidate();
+            if (IsDisposed || !IsHandleCreated) return;
+            BeginInvoke(new System.Action(Invalidate));
+        }
+
+        private void hoverTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
+        {
+            if (IsDisposed || !IsHandleCreated) return;
+            BeginInvoke(new System.Action(HoverCheck));
+        }
+
+        private void HoverCheck()
+        {
+            var graphPt = PointControlToGraph(hoverPoint);
+            LayoutPart hitPart = null;
+
+            for (var i = parts.Count - 1; i >= 0; --i)
+            {
+                if (parts[i].Path.GetBounds().Contains(graphPt) &&
+                    parts[i].Path.IsVisible(graphPt))
+                {
+                    hitPart = parts[i];
+                    break;
+                }
+            }
+
+            hoveredPart = hitPart;
+            showTooltip = hitPart != null;
+
+            if (showTooltip)
+                Invalidate();
         }
 
         private void plate_PartAdded(object sender, ItemAddedEventArgs<Part> e)
@@ -880,24 +670,9 @@ namespace OpenNest.Controls
             parts.RemoveAll(p => p.BasePart == e.Item);
         }
 
-        public void DeselectAll()
+        public void DeselectAll() => selection.DeselectAll();
-        {
+        public void SelectAll() => selection.SelectAll();
-            SelectedParts.ForEach(p => p.IsSelected = false);
+        public void NotifySelectionChanged() => selection.NotifySelectionChanged();
-            SelectedParts.Clear();
-            SelectionChanged?.Invoke(this, EventArgs.Empty);
-        }
-
-        public void SelectAll()
-        {
-            parts.ForEach(p => p.IsSelected = true);
-            SelectedParts.AddRange(parts);
-            SelectionChanged?.Invoke(this, EventArgs.Empty);
-        }
-
-        public void NotifySelectionChanged()
-        {
-            SelectionChanged?.Invoke(this, EventArgs.Empty);
-        }
 
         public override void ZoomToPoint(Vector pt, float zoomFactor, bool redraw = true)
         {
@@ -930,57 +705,15 @@ namespace OpenNest.Controls
             ZoomToArea(plate.BoundingBox(false), redraw);
         }
 
-        public void PushSelected(PushDirection direction)
+        public void PushSelected(PushDirection direction) => selection.PushSelected(direction);
-        {
-            var movingParts = SelectedParts.Select(p => p.BasePart).ToList();
-            Compactor.Push(movingParts, Plate, direction);
-            SelectedParts.ForEach(p => p.IsDirty = true);
-            Invalidate();
-        }
 
-        private string GetDisplayName(Type type)
+        public void RotateSelectedParts(double angle) => selection.RotateSelectedParts(angle);
-        {
-            var attributes = type.GetCustomAttributes(true);
-
-            foreach (var attr in attributes)
-            {
-                var displayNameAttr = attr as DisplayNameAttribute;
-
-                if (displayNameAttr != null)
-                    return displayNameAttr.DisplayName;
-            }
-
-            return type.Name;
-        }
-
-        public void RotateSelectedParts(double angle)
-        {
-            var parts = SelectedParts.Select(p => p.BasePart).ToList();
-            var bounds = parts.GetBoundingBox();
-            var center = bounds.Center;
-            var anchor = bounds.Location;
-
-            for (var i = 0; i < SelectedParts.Count; ++i)
-            {
-                var part = SelectedParts[i];
-                part.BasePart.Rotate(angle, center);
-            }
-
-            var diff = anchor - parts.GetBoundingBox().Location;
-
-            for (var i = 0; i < SelectedParts.Count; ++i)
-                SelectedParts[i].Offset(diff);
-
-            if (Plate.CutOffs.Count > 0)
-                Plate.RegenerateCutOffs(cutOffSettings);
-        }
 
         protected override void UpdateMatrix()
         {
             base.UpdateMatrix();
             parts.ForEach(p => p.Update(this));
-            stationaryParts.ForEach(p => p.Update(this));
+            previewManager.Update();
-            activeParts.ForEach(p => p.Update(this));
         }
     }
 }

OpenNest/Controls/PreviewManager.cs

@@ -0,0 +1,84 @@
+using System.Collections.Generic;
+using System.Drawing;
+
+namespace OpenNest.Controls
+{
+    internal class PreviewManager
+    {
+        private readonly PlateView view;
+        private readonly List<LayoutPart> stationaryParts = new List<LayoutPart>();
+        private readonly List<LayoutPart> activeParts = new List<LayoutPart>();
+
+        public PreviewManager(PlateView view)
+        {
+            this.view = view;
+        }
+
+        public IReadOnlyList<LayoutPart> PreviewParts =>
+            activeParts.Count > 0 ? activeParts : stationaryParts;
+
+        public Brush PreviewBrush =>
+            activeParts.Count > 0 ? view.ColorScheme.ActivePreviewPartBrush : view.ColorScheme.PreviewPartBrush;
+
+        public Pen PreviewPen =>
+            activeParts.Count > 0 ? view.ColorScheme.ActivePreviewPartPen : view.ColorScheme.PreviewPartPen;
+
+        public void SetStationaryParts(List<Part> parts)
+        {
+            stationaryParts.Clear();
+            activeParts.Clear();
+
+            if (parts != null)
+            {
+                foreach (var part in parts)
+                    stationaryParts.Add(LayoutPart.Create(part, view));
+            }
+
+            view.Invalidate();
+        }
+
+        public void SetActiveParts(List<Part> parts)
+        {
+            activeParts.Clear();
+
+            if (parts != null)
+            {
+                foreach (var part in parts)
+                    activeParts.Add(LayoutPart.Create(part, view));
+            }
+
+            view.Invalidate();
+        }
+
+        public void ClearPreviewParts()
+        {
+            stationaryParts.Clear();
+            activeParts.Clear();
+            view.Invalidate();
+        }
+
+        public void AcceptPreviewParts(List<Part> parts)
+        {
+            if (parts != null)
+            {
+                foreach (var part in parts)
+                    view.Plate.Parts.Add(part);
+            }
+
+            stationaryParts.Clear();
+            activeParts.Clear();
+        }
+
+        public void Update()
+        {
+            stationaryParts.ForEach(p => p.Update(view));
+            activeParts.ForEach(p => p.Update(view));
+        }
+
+        public void Clear()
+        {
+            stationaryParts.Clear();
+            activeParts.Clear();
+        }
+    }
+}

OpenNest/Controls/SelectionManager.cs

@@ -0,0 +1,216 @@
+using OpenNest.Engine.Fill;
+using OpenNest.Geometry;
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+
+namespace OpenNest.Controls
+{
+    internal class SelectionManager
+    {
+        private readonly PlateView view;
+        private readonly List<LayoutPart> selectedParts = new List<LayoutPart>();
+        private readonly List<CutOff> selectedCutOffs = new List<CutOff>();
+
+        public SelectionManager(PlateView view)
+        {
+            this.view = view;
+        }
+
+        public List<LayoutPart> SelectedParts => selectedParts;
+        public List<CutOff> SelectedCutOffs => selectedCutOffs;
+
+        public event EventHandler SelectionChanged;
+
+        public void DeselectAll()
+        {
+            selectedParts.ForEach(p => p.IsSelected = false);
+            selectedParts.Clear();
+            selectedCutOffs.Clear();
+            SelectionChanged?.Invoke(view, EventArgs.Empty);
+        }
+
+        public void DeselectParts()
+        {
+            selectedParts.ForEach(p => p.IsSelected = false);
+            selectedParts.Clear();
+            SelectionChanged?.Invoke(view, EventArgs.Empty);
+        }
+
+        public void DeselectCutOffs()
+        {
+            selectedCutOffs.Clear();
+            view.Invalidate();
+        }
+
+        public void SelectAll()
+        {
+            var parts = view.LayoutParts;
+            parts.ForEach(p => p.IsSelected = true);
+            selectedParts.AddRange(parts);
+            SelectionChanged?.Invoke(view, EventArgs.Empty);
+        }
+
+        public void NotifySelectionChanged()
+        {
+            SelectionChanged?.Invoke(view, EventArgs.Empty);
+        }
+
+        public void DeleteSelected()
+        {
+            if (selectedCutOffs.Count > 0)
+            {
+                foreach (var cutOff in selectedCutOffs)
+                    view.Plate.CutOffs.Remove(cutOff);
+
+                selectedCutOffs.Clear();
+                view.Plate.RegenerateCutOffs(view.CutOffSettings);
+                view.Invalidate();
+            }
+            else
+            {
+                RemoveSelectedParts();
+            }
+        }
+
+        public void RemoveSelectedParts()
+        {
+            foreach (var part in selectedParts)
+                view.Plate.Parts.Remove(part.BasePart);
+
+            DeselectAll();
+            view.Invalidate();
+        }
+
+        public void AlignSelected(AlignType alignType)
+        {
+            if (selectedParts.Count == 0)
+                return;
+
+            AlignSelected(alignType, selectedParts[0]);
+        }
+
+        public void AlignSelected(AlignType alignType, LayoutPart fixedPart)
+        {
+            switch (alignType)
+            {
+                case AlignType.Bottom:
+                    Align.Bottom(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.Horizontally:
+                    Align.Horizontally(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.Left:
+                    Align.Left(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.Right:
+                    Align.Right(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.Top:
+                    Align.Top(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.Vertically:
+                    Align.Vertically(fixedPart.BasePart, selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.EvenlySpaceHorizontally:
+                    Align.EvenlyDistributeHorizontally(selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                case AlignType.EvenlySpaceVertically:
+                    Align.EvenlyDistributeVertically(selectedParts.Select(p => p.BasePart).ToList());
+                    break;
+                default:
+                    return;
+            }
+
+            selectedParts.ForEach(p => p.IsDirty = true);
+            view.Invalidate();
+        }
+
+        public void RotateSelectedParts(double angle)
+        {
+            var parts = selectedParts.Select(p => p.BasePart).ToList();
+            var bounds = parts.GetBoundingBox();
+            var center = bounds.Center;
+            var anchor = bounds.Location;
+
+            for (var i = 0; i < selectedParts.Count; ++i)
+                selectedParts[i].BasePart.Rotate(angle, center);
+
+            var diff = anchor - parts.GetBoundingBox().Location;
+
+            for (var i = 0; i < selectedParts.Count; ++i)
+                selectedParts[i].Offset(diff);
+
+            if (view.Plate.CutOffs.Count > 0)
+                view.Plate.RegenerateCutOffs(view.CutOffSettings);
+        }
+
+        public void PushSelected(PushDirection direction)
+        {
+            var movingParts = selectedParts.Select(p => p.BasePart).ToList();
+            Compactor.Push(movingParts, view.Plate, direction);
+            selectedParts.ForEach(p => p.IsDirty = true);
+            view.Invalidate();
+        }
+
+        public LayoutPart GetPartAtControlPoint(Point pt)
+        {
+            var pt2 = view.PointControlToGraph(pt);
+            return GetPartAtGraphPoint(pt2);
+        }
+
+        public LayoutPart GetPartAtGraphPoint(PointF pt)
+        {
+            var parts = view.LayoutParts;
+            for (var i = parts.Count - 1; i >= 0; --i)
+            {
+                if (parts[i].Path.IsVisible(pt))
+                    return parts[i];
+            }
+            return null;
+        }
+
+        public LayoutPart GetPartAtPoint(Vector pt)
+        {
+            var pt2 = view.PointWorldToGraph(pt);
+            return GetPartAtGraphPoint(pt2);
+        }
+
+        public IList<LayoutPart> GetPartsFromWindow(RectangleF rect, SelectionType selectionType)
+        {
+            var list = new List<LayoutPart>();
+            var parts = view.LayoutParts;
+
+            if (selectionType == SelectionType.Intersect)
+            {
+                for (var i = 0; i < parts.Count; ++i)
+                {
+                    var part = parts[i];
+                    var region = new Region(part.Path);
+                    if (region.IsVisible(rect))
+                        list.Add(part);
+                    region.Dispose();
+                }
+            }
+            else
+            {
+                for (var i = 0; i < parts.Count; ++i)
+                {
+                    var part = parts[i];
+                    var bounds = part.Path.GetBounds();
+                    if (rect.Contains(bounds))
+                        list.Add(part);
+                }
+            }
+
+            return list;
+        }
+
+        public void Clear()
+        {
+            selectedParts.Clear();
+            selectedCutOffs.Clear();
+        }
+    }
+}

OpenNest/Controls/ShapePreviewControl.cs

@@ -0,0 +1,79 @@
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Windows.Forms;
+
+namespace OpenNest.Controls
+{
+    public class ShapePreviewControl : PlateView
+    {
+        private string[] infoLines;
+
+        public ShapePreviewControl()
+        {
+            DrawOrigin = false;
+            DrawBounds = false;
+            AllowPan = false;
+            AllowSelect = false;
+            AllowZoom = false;
+            AllowDrop = false;
+            BackColor = Color.White;
+        }
+
+        public void SetInfo(params string[] lines)
+        {
+            infoLines = lines;
+            Invalidate();
+        }
+
+        public void ShowDrawing(Drawing drawing)
+        {
+            Plate.Parts.Clear();
+            Plate.Size = new Geometry.Size(0, 0);
+
+            if (drawing?.Program != null)
+            {
+                AddPartFromDrawing(drawing, Geometry.Vector.Zero);
+                ZoomToFit();
+            }
+            else
+            {
+                Invalidate();
+            }
+        }
+
+        protected override void OnResize(System.EventArgs e)
+        {
+            base.OnResize(e);
+
+            if (Plate.Parts.Count > 0)
+                ZoomToFit(false);
+        }
+
+        protected override void OnPaint(PaintEventArgs e)
+        {
+            e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
+
+            e.Graphics.TranslateTransform(origin.X, origin.Y);
+            Renderer.DrawPlate(e.Graphics);
+            Renderer.DrawParts(e.Graphics);
+            e.Graphics.ResetTransform();
+
+            PaintInfo(e.Graphics);
+        }
+
+        private void PaintInfo(Graphics g)
+        {
+            if (infoLines == null) return;
+
+            var lineHeight = Font.GetHeight(g) + 1;
+            var y = 4f;
+
+            foreach (var line in infoLines)
+            {
+                if (string.IsNullOrEmpty(line)) continue;
+                g.DrawString(line, Font, Brushes.Black, 4, y);
+                y += lineHeight;
+            }
+        }
+    }
+}

OpenNest/Forms/BendLineDialog.resx

@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>

OpenNest/Forms/BomImportForm.cs

@@ -1,9 +1,5 @@
-using OpenNest.Bending;
-using OpenNest.CNC;
-using OpenNest.Converters;
 using OpenNest.Geometry;
 using OpenNest.IO;
-using OpenNest.IO.Bending;
 using OpenNest.IO.Bom;
 using System;
 using System.Collections.Generic;
@@ -470,33 +466,9 @@ namespace OpenNest.Forms
 
                     try
                     {
-                        var result = Dxf.Import(part.DxfPath);
+                        var drawing = CadImporter.ImportDrawing(part.DxfPath,
-
+                            new CadImportOptions { Quantity = part.Qty ?? 1 });
-                        var bends = new List<Bend>();
-                        if (result.Document != null)
-                            bends = BendDetectorRegistry.AutoDetect(result.Document);
-                        Bend.UpdateEtchEntities(result.Entities, bends);
-
-                        var drawingName = Path.GetFileNameWithoutExtension(part.DxfPath);
-                        var drawing = new Drawing(drawingName);
-                        drawing.Color = Drawing.GetNextColor();
-                        drawing.Source.Path = part.DxfPath;
-                        drawing.Quantity.Required = part.Qty ?? 1;
                         drawing.Material = new Material(material);
-                        if (bends.Count > 0)
-                            drawing.Bends.AddRange(bends);
-
-                        var normalized = ShapeProfile.NormalizeEntities(result.Entities);
-                        var pgm = ConvertGeometry.ToProgram(normalized);
-
-                        if (pgm.Codes.Count > 0 && pgm[0].Type == CodeType.RapidMove)
-                        {
-                            var rapid = (RapidMove)pgm[0];
-                            drawing.Source.Offset = rapid.EndPoint;
-                            pgm.Offset(-rapid.EndPoint);
-                        }
-
-                        drawing.Program = pgm;
                         nest.Drawings.Add(drawing);
                     }
                     catch (Exception ex)

OpenNest/Forms/CadConverterForm.cs

@@ -5,7 +5,6 @@ using OpenNest.Converters;
 using OpenNest.Geometry;
 using OpenNest.IO;
 using OpenNest.IO.Bending;
-using OpenNest.Properties;
 using System;
 using System.Collections.Generic;
 using System.Drawing;
@@ -74,36 +73,24 @@ namespace OpenNest.Forms
         {
             try
             {
-                var result = Dxf.Import(file);
+                var options = new CadImportOptions
+                {
+                    BendDetectorName = detectorIndex == 0 ? null : detectorName,
+                };
 
+                var result = CadImporter.Import(file, options);
                 if (result.Entities.Count == 0)
                     return;
 
-                // Compute bounds
-                var bounds = result.Entities.GetBoundingBox();
-
-                // Detect bends (detectorIndex/Name captured on UI thread)
-                var bends = new List<Bend>();
-                if (result.Document != null)
-                {
-                    bends = detectorIndex == 0
-                        ? BendDetectorRegistry.AutoDetect(result.Document)
-                        : BendDetectorRegistry.GetByName(detectorName)
-                            ?.DetectBends(result.Document)
-                          ?? new List<Bend>();
-                }
-
-                Bend.UpdateEtchEntities(result.Entities, bends);
-
                 var item = new FileListItem
                 {
-                    Name = Path.GetFileNameWithoutExtension(file),
+                    Name = result.Name,
                     Entities = result.Entities,
-                    Path = file,
+                    Path = result.SourcePath,
                     Quantity = 1,
                     Customer = string.Empty,
-                    Bends = bends,
+                    Bends = result.Bends,
-                    Bounds = bounds,
+                    Bounds = result.Bounds,
                     EntityCount = result.Entities.Count
                 };
 
@@ -169,6 +156,7 @@ namespace OpenNest.Forms
             if (item.Entities.Any(e => e.Layer != null))
                 item.Entities.ForEach(e => e.Layer.IsVisible = true);
             ReHidePromotedEntities(item.Bends);
+            ReHideSuppressedEntities(item);
 
             filterPanel.LoadItem(item.Entities, item.Bends);
 
@@ -245,6 +233,7 @@ namespace OpenNest.Forms
 
             filterPanel.ApplyFilters(item.Entities);
             ReHidePromotedEntities(item.Bends);
+            SyncSuppressedState(item);
             entityView1.Invalidate();
             staleProgram = true;
         }
@@ -366,7 +355,6 @@ namespace OpenNest.Forms
                 : Path.GetTempPath();
 
             var index = fileList.SelectedIndex;
-            var newItems = new List<string>();
 
             var splitWriter = new SplitDxfWriter();
             var splitItems = new List<FileListItem>();
@@ -379,7 +367,6 @@ namespace OpenNest.Forms
                 var splitPath = GetUniquePath(Path.Combine(writableDir, splitName));
 
                 splitWriter.Write(splitPath, splitDrawing);
-                newItems.Add(splitPath);
 
                 // Re-import geometry but keep bends from the split drawing
                 var result = Dxf.Import(splitPath);
@@ -604,6 +591,61 @@ namespace OpenNest.Forms
 
         #endregion
 
+        #region Load Existing Drawings
+
+        public void LoadDrawings(IEnumerable<Drawing> drawings)
+        {
+            foreach (var drawing in drawings)
+            {
+                List<Entity> entities;
+
+                if (drawing.SourceEntities != null)
+                {
+                    // Use stored entities with stable GUIDs; apply suppression state
+                    entities = new List<Entity>(drawing.SourceEntities);
+
+                    foreach (var entity in entities)
+                        entity.IsVisible = !drawing.SuppressedEntityIds.Contains(entity.Id);
+                }
+                else
+                {
+                    // Fallback: derive entities from Program (older drawings without source entities)
+                    entities = ConvertProgram.ToGeometry(drawing.Program);
+
+                    // Re-apply source offset so entities appear in their natural position
+                    if (drawing.Source?.Offset != null && drawing.Source.Offset != Vector.Zero)
+                    {
+                        foreach (var entity in entities)
+                            entity.Offset(drawing.Source.Offset);
+                    }
+
+                    // Remove rapid traversals — they aren't part of the cut geometry
+                    entities.RemoveAll(e => e.Layer == SpecialLayers.Rapid);
+                }
+
+                var bounds = entities.GetBoundingBox();
+
+                var item = new FileListItem
+                {
+                    Name = drawing.Name,
+                    Entities = entities,
+                    Path = drawing.Source?.Path,
+                    Quantity = drawing.Quantity.Required,
+                    Customer = drawing.Customer ?? string.Empty,
+                    Bends = drawing.Bends?.ToList() ?? new List<Bend>(),
+                    SuppressedEntityIds = drawing.SuppressedEntityIds.Count > 0
+                        ? new HashSet<Guid>(drawing.SuppressedEntityIds)
+                        : null,
+                    Bounds = bounds,
+                    EntityCount = entities.Count
+                };
+
+                fileList.AddItem(item);
+            }
+        }
+
+        #endregion
+
         #region Output
 
         public List<Drawing> GetDrawings()
@@ -612,38 +654,36 @@ namespace OpenNest.Forms
 
             foreach (var item in fileList.Items)
             {
-                var entities = item.Entities.Where(e => e.Layer.IsVisible && e.IsVisible).ToList();
+                var visible = item.Entities
+                    .Where(e => e.Layer.IsVisible && e.IsVisible)
+                    .ToList();
 
-                if (entities.Count == 0)
+                if (visible.Count == 0)
                     continue;
 
-                var drawing = new Drawing(item.Name);
+                // Rebuild a CadImportResult from the FileListItem's current state so
-                drawing.Color = Drawing.GetNextColor();
+                // BuildDrawing sees the user's edits (filters, suppressions, new bends).
-                drawing.Customer = item.Customer;
+                var result = new CadImportResult
-                drawing.Source.Path = item.Path;
-                drawing.Quantity.Required = item.Quantity;
-
-                // Copy bends
-                if (item.Bends != null)
-                    drawing.Bends.AddRange(item.Bends);
-
-                var normalized = ShapeProfile.NormalizeEntities(entities);
-                var pgm = ConvertGeometry.ToProgram(normalized);
-                var firstCode = pgm[0];
-
-                if (firstCode.Type == CodeType.RapidMove)
                 {
-                    var rapid = (RapidMove)firstCode;
+                    Entities = item.Entities,
-                    drawing.Source.Offset = rapid.EndPoint;
+                    Bends = item.Bends ?? new List<Bend>(),
-                    pgm.Offset(-rapid.EndPoint);
+                    Bounds = item.Bounds,
-                    // Keep the rapid (now at origin) — it marks the contour
+                    SourcePath = item.Path,
-                    // start and is needed by the post for correct pierce placement.
+                    Name = item.Name,
-                }
+                };
+
+                var editedProgram = (item == CurrentItem && programEditor.IsDirty && programEditor.Program != null)
+                    ? programEditor.Program
+                    : null;
+
+                var drawing = CadImporter.BuildDrawing(
+                    result,
+                    visible,
+                    result.Bends,
+                    item.Quantity,
+                    item.Customer,
+                    editedProgram);
 
-                if (item == CurrentItem && programEditor.IsDirty && programEditor.Program != null)
-                    drawing.Program = programEditor.Program;
-                else
-                    drawing.Program = pgm;
                 drawings.Add(drawing);
 
                 Thread.Sleep(20);
@@ -666,8 +706,46 @@ namespace OpenNest.Forms
             }
         }
 
+        private static void ReHideSuppressedEntities(FileListItem item)
+        {
+            if (item.SuppressedEntityIds == null || item.SuppressedEntityIds.Count == 0)
+                return;
 
-        private static Color GetNextColor() => Drawing.GetNextColor();
+            foreach (var entity in item.Entities)
+            {
+                if (item.SuppressedEntityIds.Contains(entity.Id))
+                    entity.IsVisible = false;
+            }
+
+            // If all entities on a layer are suppressed, uncheck the layer too
+            var layerGroups = item.Entities
+                .Where(e => e.Layer != null)
+                .GroupBy(e => e.Layer);
+
+            foreach (var group in layerGroups)
+            {
+                if (group.All(e => !e.IsVisible))
+                    group.Key.IsVisible = false;
+            }
+        }
+
+        private static void SyncSuppressedState(FileListItem item)
+        {
+            var bendSources = new HashSet<Entity>(
+                (item.Bends ?? new List<Bend>())
+                    .Where(b => b.SourceEntity != null)
+                    .Select(b => b.SourceEntity));
+
+            var suppressed = item.Entities
+                .Where(e => !(e.Layer.IsVisible && e.IsVisible))
+                .Where(e => !bendSources.Contains(e))
+                .Select(e => e.Id);
+
+            item.SuppressedEntityIds = new HashSet<Guid>(suppressed);
+
+            if (item.SuppressedEntityIds.Count == 0)
+                item.SuppressedEntityIds = null;
+        }
 
         private static bool IsDirectoryWritable(string path)
         {

OpenNest/Forms/CuttingParametersDialog.cs

@@ -0,0 +1,68 @@
+using OpenNest.CNC.CuttingStrategy;
+using OpenNest.Controls;
+using System.Drawing;
+using System.Windows.Forms;
+
+namespace OpenNest.Forms
+{
+    public class CuttingParametersDialog : Form
+    {
+        private readonly CuttingPanel cuttingPanel;
+
+        public CuttingParametersDialog()
+        {
+            Text = "Cutting Parameters";
+            Size = new Size(400, 560);
+            FormBorderStyle = FormBorderStyle.FixedDialog;
+            MaximizeBox = false;
+            MinimizeBox = false;
+            StartPosition = FormStartPosition.CenterParent;
+
+            cuttingPanel = new CuttingPanel
+            {
+                Dock = DockStyle.Fill
+            };
+
+            var buttonPanel = new Panel
+            {
+                Dock = DockStyle.Bottom,
+                Height = 40
+            };
+
+            var btnOk = new Button
+            {
+                Text = "OK",
+                DialogResult = DialogResult.OK,
+                Size = new Size(80, 28),
+                Location = new Point(220, 6)
+            };
+
+            var btnCancel = new Button
+            {
+                Text = "Cancel",
+                DialogResult = DialogResult.Cancel,
+                Size = new Size(80, 28),
+                Location = new Point(305, 6)
+            };
+
+            buttonPanel.Controls.Add(btnOk);
+            buttonPanel.Controls.Add(btnCancel);
+
+            Controls.Add(cuttingPanel);
+            Controls.Add(buttonPanel);
+
+            AcceptButton = btnOk;
+            CancelButton = btnCancel;
+        }
+
+        public void LoadParameters(CuttingParameters parameters)
+        {
+            cuttingPanel.LoadFromParameters(parameters);
+        }
+
+        public CuttingParameters GetParameters()
+        {
+            return cuttingPanel.BuildParameters();
+        }
+    }
+}

OpenNest/Forms/CuttingParametersSerializer.cs

@@ -24,6 +24,8 @@ namespace OpenNest.Forms
                 TabsEnabled = p.TabsEnabled,
                 TabWidth = p.TabConfig?.Size ?? 0.25,
                 PierceClearance = p.PierceClearance,
+                RoundLeadInAngles = p.RoundLeadInAngles,
+                LeadInAngleIncrement = p.LeadInAngleIncrement,
                 AutoTabMinSize = p.AutoTabMinSize,
                 AutoTabMaxSize = p.AutoTabMaxSize
             };
@@ -47,6 +49,8 @@ namespace OpenNest.Forms
                 TabsEnabled = dto.TabsEnabled,
                 TabConfig = new NormalTab { Size = dto.TabWidth },
                 PierceClearance = dto.PierceClearance,
+                RoundLeadInAngles = dto.RoundLeadInAngles,
+                LeadInAngleIncrement = dto.LeadInAngleIncrement > 0 ? dto.LeadInAngleIncrement : 5.0,
                 AutoTabMinSize = dto.AutoTabMinSize,
                 AutoTabMaxSize = dto.AutoTabMaxSize
             };
@@ -85,7 +89,6 @@ namespace OpenNest.Forms
             {
                 LineLeadOut line => new LeadOutDto { Type = "Line", Length = line.Length, ApproachAngle = line.ApproachAngle },
                 ArcLeadOut arc => new LeadOutDto { Type = "Arc", Radius = arc.Radius },
-                MicrotabLeadOut mt => new LeadOutDto { Type = "Microtab", GapSize = mt.GapSize },
                 _ => new LeadOutDto { Type = "None" }
             };
         }
@@ -97,7 +100,6 @@ namespace OpenNest.Forms
             {
                 "Line" => new LineLeadOut { Length = dto.Length, ApproachAngle = dto.ApproachAngle },
                 "Arc" => new ArcLeadOut { Radius = dto.Radius },
-                "Microtab" => new MicrotabLeadOut { GapSize = dto.GapSize },
                 _ => new NoLeadOut()
             };
         }
@@ -113,6 +115,8 @@ namespace OpenNest.Forms
             public bool TabsEnabled { get; set; }
             public double TabWidth { get; set; }
             public double PierceClearance { get; set; }
+            public bool RoundLeadInAngles { get; set; }
+            public double LeadInAngleIncrement { get; set; }
             public double AutoTabMinSize { get; set; }
             public double AutoTabMaxSize { get; set; }
         }

OpenNest/Forms/EditNestForm.Designer.cs

@@ -47,6 +47,8 @@
             drawingListBox1 = new OpenNest.Controls.DrawingListBox();
             toolStrip2 = new System.Windows.Forms.ToolStrip();
             toolStripButton2 = new System.Windows.Forms.ToolStripButton();
+            toolStripSeparator4 = new System.Windows.Forms.ToolStripSeparator();
+            editDrawingsButton = new System.Windows.Forms.ToolStripButton();
             toolStripSeparator1 = new System.Windows.Forms.ToolStripSeparator();
             toolStripButton3 = new System.Windows.Forms.ToolStripButton();
             toolStripSeparator2 = new System.Windows.Forms.ToolStripSeparator();
@@ -79,8 +81,8 @@
             // 
             // tabControl1
             // 
-            tabControl1.Controls.Add(tabPage1);
             tabControl1.Controls.Add(tabPage2);
+            tabControl1.Controls.Add(tabPage1);
             tabControl1.Dock = System.Windows.Forms.DockStyle.Fill;
             tabControl1.ItemSize = new System.Drawing.Size(100, 22);
             tabControl1.Location = new System.Drawing.Point(0, 0);
@@ -175,7 +177,7 @@
             // toolStripLabel2
             // 
             toolStripLabel2.DisplayStyle = System.Windows.Forms.ToolStripItemDisplayStyle.Image;
-            toolStripLabel2.Image = Properties.Resources.delete;
+            toolStripLabel2.Image = (System.Drawing.Image)resources.GetObject("toolStripLabel2.Image");
             toolStripLabel2.Name = "toolStripLabel2";
             toolStripLabel2.Padding = new System.Windows.Forms.Padding(5, 0, 5, 0);
             toolStripLabel2.Size = new System.Drawing.Size(34, 24);
@@ -217,7 +219,7 @@
             // 
             toolStrip2.GripStyle = System.Windows.Forms.ToolStripGripStyle.Hidden;
             toolStrip2.ImageScalingSize = new System.Drawing.Size(20, 20);
-            toolStrip2.Items.AddRange(new System.Windows.Forms.ToolStripItem[] { toolStripButton2, toolStripSeparator1, toolStripButton3, toolStripSeparator2, hideNestedButton });
+            toolStrip2.Items.AddRange(new System.Windows.Forms.ToolStripItem[] { toolStripButton2, toolStripSeparator4, editDrawingsButton, toolStripSeparator1, toolStripButton3, toolStripSeparator2, hideNestedButton });
             toolStrip2.Location = new System.Drawing.Point(4, 3);
             toolStrip2.Name = "toolStrip2";
             toolStrip2.Size = new System.Drawing.Size(265, 27);
@@ -236,6 +238,21 @@
             toolStripButton2.Text = "Import Drawings";
             toolStripButton2.Click += ImportDrawings_Click;
             // 
+            // toolStripSeparator4
+            // 
+            toolStripSeparator4.Name = "toolStripSeparator4";
+            toolStripSeparator4.Size = new System.Drawing.Size(6, 27);
+            // 
+            // editDrawingsButton
+            // 
+            editDrawingsButton.DisplayStyle = System.Windows.Forms.ToolStripItemDisplayStyle.Image;
+            editDrawingsButton.Image = (System.Drawing.Image)resources.GetObject("editDrawingsButton.Image");
+            editDrawingsButton.Name = "editDrawingsButton";
+            editDrawingsButton.Padding = new System.Windows.Forms.Padding(5, 0, 5, 0);
+            editDrawingsButton.Size = new System.Drawing.Size(34, 24);
+            editDrawingsButton.Text = "Edit Drawings in Converter";
+            editDrawingsButton.Click += EditDrawingsInConverter_Click;
+            // 
             // toolStripSeparator1
             // 
             toolStripSeparator1.Name = "toolStripSeparator1";
@@ -312,6 +329,8 @@
         private System.Windows.Forms.ColumnHeader utilColumn;
         private System.Windows.Forms.ToolStrip toolStrip2;
         private System.Windows.Forms.ToolStripButton toolStripButton2;
+        private System.Windows.Forms.ToolStripSeparator toolStripSeparator4;
+        private System.Windows.Forms.ToolStripButton editDrawingsButton;
         private System.Windows.Forms.ToolStripSeparator toolStripSeparator1;
         private System.Windows.Forms.ToolStripButton toolStripButton3;
         private System.Windows.Forms.ToolStripSeparator toolStripSeparator2;

OpenNest/Forms/EditNestForm.cs

@@ -52,6 +52,7 @@ namespace OpenNest.Forms
         private EditNestForm()
         {
             PlateView = new PlateView();
+            PlateView.MouseEnter += PlateView_MouseEnter;
             PlateView.Enter += PlateView_Enter;
             PlateView.PartAdded += PlateView_PartAdded;
             PlateView.PartRemoved += PlateView_PartRemoved;
@@ -718,19 +719,17 @@ namespace OpenNest.Forms
 
             var plate = PlateView.Plate;
 
-            if (plate.CuttingParameters == null)
+            var parameters = LoadOrDefaultParameters(plate.CuttingParameters);
-            {
+
-                var json = Properties.Settings.Default.CuttingParametersJson;
+            using var dlg = new CuttingParametersDialog();
-                if (!string.IsNullOrEmpty(json))
+            dlg.LoadParameters(parameters);
-                {
+
-                    try { plate.CuttingParameters = CuttingParametersSerializer.Deserialize(json); }
+            if (dlg.ShowDialog() != DialogResult.OK)
-                    catch { plate.CuttingParameters = new CuttingParameters(); }
+                return;
-                }
+
-                else
+            parameters = dlg.GetParameters();
-                {
+            plate.CuttingParameters = parameters;
-                    plate.CuttingParameters = new CuttingParameters();
+            SaveCuttingParameters(parameters);
-                }
-            }
 
             var assigner = new LeadInAssigner
             {
@@ -781,17 +780,16 @@ namespace OpenNest.Forms
             if (Nest == null)
                 return;
 
-            CuttingParameters parameters;
+            var parameters = LoadOrDefaultParameters(PlateView?.Plate?.CuttingParameters);
-            var json = Properties.Settings.Default.CuttingParametersJson;
+
-            if (!string.IsNullOrEmpty(json))
+            using var dlg = new CuttingParametersDialog();
-            {
+            dlg.LoadParameters(parameters);
-                try { parameters = CuttingParametersSerializer.Deserialize(json); }
+
-                catch { parameters = new CuttingParameters(); }
+            if (dlg.ShowDialog() != DialogResult.OK)
-            }
+                return;
-            else
+
-            {
+            parameters = dlg.GetParameters();
-                parameters = new CuttingParameters();
+            SaveCuttingParameters(parameters);
-            }
 
             var assigner = new LeadInAssigner
             {
@@ -839,29 +837,88 @@ namespace OpenNest.Forms
 
             var plate = PlateView.Plate;
 
-            // If no cutting parameters exist, initialize from saved settings or defaults
             if (plate.CuttingParameters == null)
-            {
+                plate.CuttingParameters = LoadOrDefaultParameters(null);
-                var json = Properties.Settings.Default.CuttingParametersJson;
-                if (!string.IsNullOrEmpty(json))
-                {
-                    try { plate.CuttingParameters = CuttingParametersSerializer.Deserialize(json); }
-                    catch { plate.CuttingParameters = new CuttingParameters(); }
-                }
-                else
-                {
-                    plate.CuttingParameters = new CuttingParameters();
-                }
-            }
 
             PlateView.SetAction(typeof(Actions.ActionLeadIn));
         }
 
+        private static CuttingParameters LoadOrDefaultParameters(CuttingParameters existing)
+        {
+            if (existing != null)
+                return existing;
+
+            var json = Properties.Settings.Default.CuttingParametersJson;
+            if (!string.IsNullOrEmpty(json))
+            {
+                try { return CuttingParametersSerializer.Deserialize(json); }
+                catch { /* fall through */ }
+            }
+
+            return new CuttingParameters();
+        }
+
+        private static void SaveCuttingParameters(CuttingParameters parameters)
+        {
+            var json = CuttingParametersSerializer.Serialize(parameters);
+            Properties.Settings.Default.CuttingParametersJson = json;
+            Properties.Settings.Default.Save();
+        }
+
         private void ImportDrawings_Click(object sender, EventArgs e)
         {
             Import();
         }
 
+        private void EditDrawingsInConverter_Click(object sender, EventArgs e)
+        {
+            if (Nest.Drawings.Count == 0)
+                return;
+
+            var converter = new CadConverterForm();
+            converter.LoadDrawings(Nest.Drawings);
+
+            if (converter.ShowDialog() != DialogResult.OK)
+                return;
+
+            var newDrawings = converter.GetDrawings();
+            var newByName = newDrawings.ToDictionary(d => d.Name);
+
+            // Update existing drawings in-place so parts keep their BaseDrawing references
+            foreach (var existing in Nest.Drawings.ToList())
+            {
+                if (newByName.TryGetValue(existing.Name, out var updated))
+                {
+                    existing.Program = updated.Program;
+                    existing.SourceEntities = updated.SourceEntities;
+                    existing.SuppressedEntityIds = updated.SuppressedEntityIds;
+                    existing.Source = updated.Source;
+                    existing.Customer = updated.Customer;
+                    existing.Quantity.Required = updated.Quantity.Required;
+                    existing.Bends.Clear();
+                    existing.Bends.AddRange(updated.Bends);
+                    newByName.Remove(existing.Name);
+                }
+                else
+                {
+                    Nest.Drawings.Remove(existing);
+                }
+            }
+
+            // Add any new drawings that weren't in the original set
+            foreach (var d in newByName.Values)
+                Nest.Drawings.Add(d);
+
+            // Refresh all parts to use the updated programs
+            foreach (var plate in Nest.Plates)
+                foreach (var part in plate.Parts)
+                    if (!part.BaseDrawing.IsCutOff)
+                        part.Update();
+
+            UpdateDrawingList();
+            PlateView.Invalidate();
+        }
+
         private void CleanUnusedDrawings_Click(object sender, EventArgs e)
         {
             var result = MessageBox.Show(
@@ -892,6 +949,7 @@ namespace OpenNest.Forms
             PlateView.Plate = PlateManager.CurrentPlate;
             PlateView.ZoomToFit();
             UpdatePlateHeader();
+            UpdateRemovePlateButton();
             PlateChanged?.Invoke(this, EventArgs.Empty);
         }
 
@@ -1025,6 +1083,12 @@ namespace OpenNest.Forms
             addPart = true;
         }
 
+        private void PlateView_MouseEnter(object sender, EventArgs e)
+        {
+            if (!PlateView.Focused)
+                PlateView.Focus();
+        }
+
         private void PlateView_Enter(object sender, EventArgs e)
         {
             if (!addPart)

OpenNest/Forms/EditNestInfoForm.Designer.cs

@@ -63,7 +63,7 @@
             this.textBox2 = new System.Windows.Forms.TextBox();
             this.label5 = new System.Windows.Forms.Label();
             this.labelMaterial = new System.Windows.Forms.Label();
-            this.materialBox = new System.Windows.Forms.TextBox();
+            this.materialBox = new System.Windows.Forms.ComboBox();
             this.tabPage2 = new System.Windows.Forms.TabPage();
             this.tabPage3 = new System.Windows.Forms.TabPage();
             this.notesBox = new System.Windows.Forms.TextBox();
@@ -516,9 +516,10 @@
             // materialBox
             //
             this.materialBox.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Left | System.Windows.Forms.AnchorStyles.Right)));
+            this.materialBox.FormattingEnabled = true;
             this.materialBox.Location = new System.Drawing.Point(135, 159);
             this.materialBox.Name = "materialBox";
-            this.materialBox.Size = new System.Drawing.Size(224, 22);
+            this.materialBox.Size = new System.Drawing.Size(224, 24);
             this.materialBox.TabIndex = 11;
             //
             // label3
@@ -729,6 +730,6 @@
         private System.Windows.Forms.RadioButton radioButton2;
         private System.Windows.Forms.Label label5;
         private System.Windows.Forms.Label labelMaterial;
-        private System.Windows.Forms.TextBox materialBox;
+        private System.Windows.Forms.ComboBox materialBox;
     }
 }

OpenNest/Forms/EditNestInfoForm.cs

@@ -15,6 +15,9 @@ namespace OpenNest.Forms
         {
             InitializeComponent();
 
+            foreach (var name in PostProcessorMaterials.Names)
+                materialBox.Items.Add(name);
+
             timer = new Timer
             {
                 SynchronizingObject = this,

OpenNest/Forms/MainForm.Designer.cs

@@ -85,6 +85,7 @@
             mnuNest = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestEdit = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestImportDrawing = new System.Windows.Forms.ToolStripMenuItem();
+            mnuNestShapeLibrary = new System.Windows.Forms.ToolStripMenuItem();
             toolStripMenuItem7 = new System.Windows.Forms.ToolStripSeparator();
             mnuNestFirstPlate = new System.Windows.Forms.ToolStripMenuItem();
             mnuNestLastPlate = new System.Windows.Forms.ToolStripMenuItem();
@@ -559,7 +560,7 @@
             // 
             // mnuNest
             // 
-            mnuNest.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] { mnuNestEdit, mnuNestImportDrawing, toolStripMenuItem7, mnuNestFirstPlate, mnuNestLastPlate, toolStripMenuItem6, mnuNestNextPlate, mnuNestPreviousPlate, toolStripMenuItem12, runAutoNestToolStripMenuItem, autoSequenceAllPlatesToolStripMenuItem, mnuNestRemoveEmptyPlates, mnuNestPost, toolStripMenuItem19, calculateCutTimeToolStripMenuItem, toolStripMenuItem22, mnuNestAssignLeadIns, mnuNestRemoveLeadIns });
+            mnuNest.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] { mnuNestEdit, mnuNestImportDrawing, mnuNestShapeLibrary, toolStripMenuItem7, mnuNestFirstPlate, mnuNestLastPlate, toolStripMenuItem6, mnuNestNextPlate, mnuNestPreviousPlate, toolStripMenuItem12, runAutoNestToolStripMenuItem, autoSequenceAllPlatesToolStripMenuItem, mnuNestRemoveEmptyPlates, mnuNestPost, toolStripMenuItem19, calculateCutTimeToolStripMenuItem, toolStripMenuItem22, mnuNestAssignLeadIns, mnuNestRemoveLeadIns });
             mnuNest.Name = "mnuNest";
             mnuNest.Size = new System.Drawing.Size(43, 20);
             mnuNest.Text = "&Nest";
@@ -578,7 +579,14 @@
             mnuNestImportDrawing.Size = new System.Drawing.Size(205, 22);
             mnuNestImportDrawing.Text = "Import Drawing";
             mnuNestImportDrawing.Click += Import_Click;
-            // 
+            //
+            // mnuNestShapeLibrary
+            //
+            mnuNestShapeLibrary.Name = "mnuNestShapeLibrary";
+            mnuNestShapeLibrary.Size = new System.Drawing.Size(205, 22);
+            mnuNestShapeLibrary.Text = "Shape Library";
+            mnuNestShapeLibrary.Click += ShapeLibrary_Click;
+            //
             // toolStripMenuItem7
             // 
             toolStripMenuItem7.Name = "toolStripMenuItem7";
@@ -1213,6 +1221,7 @@
         private System.Windows.Forms.ToolStripMenuItem mnuNest;
         private System.Windows.Forms.ToolStripMenuItem mnuNestEdit;
         private System.Windows.Forms.ToolStripMenuItem mnuNestImportDrawing;
+        private System.Windows.Forms.ToolStripMenuItem mnuNestShapeLibrary;
         private System.Windows.Forms.ToolStripSeparator toolStripMenuItem7;
         private System.Windows.Forms.ToolStripMenuItem mnuNestFirstPlate;
         private System.Windows.Forms.ToolStripMenuItem mnuNestLastPlate;

OpenNest/Forms/MainForm.cs

@@ -351,6 +351,9 @@ namespace OpenNest.Forms
                         postProcessorMenuItem.Tag = postProcessor;
                         postProcessorMenuItem.Click += PostProcessor_Click;
                         mnuNestPost.DropDownItems.Add(postProcessorMenuItem);
+
+                        if (postProcessor is IMaterialProvidingPostProcessor materialProvider)
+                            PostProcessorMaterials.AddFrom(materialProvider);
                     }
                 }
             }
@@ -829,6 +832,20 @@ namespace OpenNest.Forms
             activeForm.Import();
         }
 
+        private void ShapeLibrary_Click(object sender, EventArgs e)
+        {
+            if (activeForm == null) return;
+
+            var form = new ShapeLibraryForm();
+            form.ShowDialog();
+
+            var drawings = form.GetDrawings();
+            if (drawings.Count == 0) return;
+
+            drawings.ForEach(d => activeForm.Nest.Drawings.Add(d));
+            activeForm.UpdateDrawingList();
+        }
+
         private void EditNest_Click(object sender, EventArgs e)
         {
             if (activeForm == null) return;
@@ -1006,9 +1023,18 @@ namespace OpenNest.Forms
 
                 var template = activeForm.PlateView.Plate;
 
+                var nestOptions = new MultiPlateNestOptions
+                {
+                    Template = template,
+                    PlateOptions = plateOptions,
+                    SalvageRate = salvageRate,
+                    SortOrder = sortOrder,
+                    MinRemnantSize = minRemnantSize,
+                    AllowPlateCreation = allowPlateCreation,
+                };
+
                 var result = await Task.Run(() =>
-                    MultiPlateNester.Nest(items, template, plateOptions, salvageRate,
+                    MultiPlateNester.Nest(items, nestOptions, existingPlates, progress, token));
-                        sortOrder, minRemnantSize, allowPlateCreation, existingPlates, progress, token));
 
                 foreach (var pr in result.Plates)
                 {
@@ -1134,6 +1160,9 @@ namespace OpenNest.Forms
             if (postProcessor == null)
                 return;
 
+            if (postProcessor is IPostProcessorNestAware nestAware)
+                nestAware.PrepareForNest(activeForm.Nest);
+
             if (postProcessor is IConfigurablePostProcessor configurable)
             {
                 using var configForm = new PostProcessorConfigForm(configurable);

OpenNest/Forms/NestProgressForm.Designer.cs

@@ -427,7 +427,7 @@ namespace OpenNest.Forms
             plate1.Quantity = 0;
             previewPlateView.Plate = plate1;
             previewPlateView.RotateIncrementAngle = 10D;
-            previewPlateView.SelectedCutOff = null;
+
             previewPlateView.ShowBendLines = false;
             previewPlateView.Size = new System.Drawing.Size(356, 341);
             previewPlateView.Status = "Select";

OpenNest/Forms/ShapeLibraryForm.Designer.cs

@@ -0,0 +1,338 @@
+namespace OpenNest.Forms
+{
+    partial class ShapeLibraryForm
+    {
+        private System.ComponentModel.IContainer components = null;
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        private void InitializeComponent()
+        {
+            ColorScheme colorScheme1 = new ColorScheme();
+            CutOffSettings cutOffSettings1 = new CutOffSettings();
+            Plate plate1 = new Plate();
+            Collections.ObservableList<CutOff> observableList_11 = new Collections.ObservableList<CutOff>();
+            Collections.ObservableList<Part> observableList_12 = new Collections.ObservableList<Part>();
+            splitContainer = new System.Windows.Forms.SplitContainer();
+            shapeListBox = new System.Windows.Forms.ListBox();
+            layoutTable = new System.Windows.Forms.TableLayoutPanel();
+            fieldsTable = new System.Windows.Forms.TableLayoutPanel();
+            nameLabel = new System.Windows.Forms.Label();
+            nameTextBox = new System.Windows.Forms.TextBox();
+            qtyLabel = new System.Windows.Forms.Label();
+            quantityUpDown = new OpenNest.Controls.NumericUpDown();
+            configLabel = new System.Windows.Forms.Label();
+            configComboBox = new System.Windows.Forms.ComboBox();
+            contentPanel = new System.Windows.Forms.Panel();
+            previewBox = new OpenNest.Controls.ShapePreviewControl();
+            parametersPanel = new System.Windows.Forms.Panel();
+            buttonPanel = new System.Windows.Forms.Panel();
+            addButton = new System.Windows.Forms.Button();
+            closeButton = new System.Windows.Forms.Button();
+            ((System.ComponentModel.ISupportInitialize)splitContainer).BeginInit();
+            splitContainer.Panel1.SuspendLayout();
+            splitContainer.Panel2.SuspendLayout();
+            splitContainer.SuspendLayout();
+            layoutTable.SuspendLayout();
+            fieldsTable.SuspendLayout();
+            ((System.ComponentModel.ISupportInitialize)quantityUpDown).BeginInit();
+            contentPanel.SuspendLayout();
+            buttonPanel.SuspendLayout();
+            SuspendLayout();
+            // 
+            // splitContainer
+            // 
+            splitContainer.Dock = System.Windows.Forms.DockStyle.Fill;
+            splitContainer.FixedPanel = System.Windows.Forms.FixedPanel.Panel1;
+            splitContainer.Location = new System.Drawing.Point(0, 0);
+            splitContainer.Name = "splitContainer";
+            // 
+            // splitContainer.Panel1
+            // 
+            splitContainer.Panel1.Controls.Add(shapeListBox);
+            // 
+            // splitContainer.Panel2
+            // 
+            splitContainer.Panel2.Controls.Add(layoutTable);
+            splitContainer.Size = new System.Drawing.Size(750, 520);
+            splitContainer.SplitterDistance = 150;
+            splitContainer.TabIndex = 0;
+            // 
+            // shapeListBox
+            // 
+            shapeListBox.BorderStyle = System.Windows.Forms.BorderStyle.None;
+            shapeListBox.Dock = System.Windows.Forms.DockStyle.Fill;
+            shapeListBox.DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed;
+            shapeListBox.Font = new System.Drawing.Font("Segoe UI", 10F);
+            shapeListBox.IntegralHeight = false;
+            shapeListBox.ItemHeight = 32;
+            shapeListBox.Location = new System.Drawing.Point(0, 0);
+            shapeListBox.Name = "shapeListBox";
+            shapeListBox.Size = new System.Drawing.Size(150, 520);
+            shapeListBox.TabIndex = 0;
+            // 
+            // layoutTable
+            // 
+            layoutTable.ColumnCount = 1;
+            layoutTable.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle(System.Windows.Forms.SizeType.Percent, 100F));
+            layoutTable.Controls.Add(fieldsTable, 0, 0);
+            layoutTable.Controls.Add(contentPanel, 0, 1);
+            layoutTable.Controls.Add(buttonPanel, 0, 2);
+            layoutTable.Dock = System.Windows.Forms.DockStyle.Fill;
+            layoutTable.Location = new System.Drawing.Point(0, 0);
+            layoutTable.Name = "layoutTable";
+            layoutTable.Padding = new System.Windows.Forms.Padding(6, 4, 6, 0);
+            layoutTable.RowCount = 3;
+            layoutTable.RowStyles.Add(new System.Windows.Forms.RowStyle());
+            layoutTable.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
+            layoutTable.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Absolute, 44F));
+            layoutTable.Size = new System.Drawing.Size(596, 520);
+            layoutTable.TabIndex = 0;
+            // 
+            // fieldsTable
+            // 
+            fieldsTable.AutoSize = true;
+            fieldsTable.ColumnCount = 2;
+            fieldsTable.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle());
+            fieldsTable.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle(System.Windows.Forms.SizeType.Percent, 100F));
+            fieldsTable.Controls.Add(nameLabel, 0, 0);
+            fieldsTable.Controls.Add(nameTextBox, 1, 0);
+            fieldsTable.Controls.Add(qtyLabel, 0, 1);
+            fieldsTable.Controls.Add(quantityUpDown, 1, 1);
+            fieldsTable.Controls.Add(configLabel, 0, 2);
+            fieldsTable.Controls.Add(configComboBox, 1, 2);
+            fieldsTable.Dock = System.Windows.Forms.DockStyle.Fill;
+            fieldsTable.Location = new System.Drawing.Point(6, 4);
+            fieldsTable.Margin = new System.Windows.Forms.Padding(0, 0, 0, 4);
+            fieldsTable.Name = "fieldsTable";
+            fieldsTable.RowCount = 3;
+            fieldsTable.RowStyles.Add(new System.Windows.Forms.RowStyle());
+            fieldsTable.RowStyles.Add(new System.Windows.Forms.RowStyle());
+            fieldsTable.RowStyles.Add(new System.Windows.Forms.RowStyle());
+            fieldsTable.Size = new System.Drawing.Size(584, 99);
+            fieldsTable.TabIndex = 0;
+            // 
+            // nameLabel
+            // 
+            nameLabel.Anchor = System.Windows.Forms.AnchorStyles.Left;
+            nameLabel.AutoSize = true;
+            nameLabel.Location = new System.Drawing.Point(4, 8);
+            nameLabel.Margin = new System.Windows.Forms.Padding(4, 4, 8, 4);
+            nameLabel.Name = "nameLabel";
+            nameLabel.Size = new System.Drawing.Size(46, 17);
+            nameLabel.TabIndex = 0;
+            nameLabel.Text = "Name:";
+            // 
+            // nameTextBox
+            // 
+            nameTextBox.Anchor = System.Windows.Forms.AnchorStyles.Left | System.Windows.Forms.AnchorStyles.Right;
+            nameTextBox.Location = new System.Drawing.Point(106, 4);
+            nameTextBox.Margin = new System.Windows.Forms.Padding(4);
+            nameTextBox.Name = "nameTextBox";
+            nameTextBox.Size = new System.Drawing.Size(474, 25);
+            nameTextBox.TabIndex = 1;
+            // 
+            // qtyLabel
+            // 
+            qtyLabel.Anchor = System.Windows.Forms.AnchorStyles.Left;
+            qtyLabel.AutoSize = true;
+            qtyLabel.Location = new System.Drawing.Point(4, 41);
+            qtyLabel.Margin = new System.Windows.Forms.Padding(4, 4, 8, 4);
+            qtyLabel.Name = "qtyLabel";
+            qtyLabel.Size = new System.Drawing.Size(59, 17);
+            qtyLabel.TabIndex = 2;
+            qtyLabel.Text = "Quantity:";
+            // 
+            // quantityUpDown
+            // 
+            quantityUpDown.Location = new System.Drawing.Point(106, 37);
+            quantityUpDown.Margin = new System.Windows.Forms.Padding(4);
+            quantityUpDown.Maximum = new decimal(new int[] { 999999, 0, 0, 0 });
+            quantityUpDown.Minimum = new decimal(new int[] { 1, 0, 0, 0 });
+            quantityUpDown.Name = "quantityUpDown";
+            quantityUpDown.Size = new System.Drawing.Size(100, 25);
+            quantityUpDown.Suffix = "";
+            quantityUpDown.TabIndex = 2;
+            quantityUpDown.Value = new decimal(new int[] { 1, 0, 0, 0 });
+            // 
+            // configLabel
+            // 
+            configLabel.Anchor = System.Windows.Forms.AnchorStyles.Left;
+            configLabel.AutoSize = true;
+            configLabel.Location = new System.Drawing.Point(4, 74);
+            configLabel.Margin = new System.Windows.Forms.Padding(4, 4, 8, 4);
+            configLabel.Name = "configLabel";
+            configLabel.Size = new System.Drawing.Size(90, 17);
+            configLabel.TabIndex = 3;
+            configLabel.Text = "Configuration:";
+            configLabel.Visible = false;
+            // 
+            // configComboBox
+            // 
+            configComboBox.Anchor = System.Windows.Forms.AnchorStyles.Left | System.Windows.Forms.AnchorStyles.Right;
+            configComboBox.DropDownStyle = System.Windows.Forms.ComboBoxStyle.DropDownList;
+            configComboBox.Location = new System.Drawing.Point(106, 70);
+            configComboBox.Margin = new System.Windows.Forms.Padding(4);
+            configComboBox.Name = "configComboBox";
+            configComboBox.Size = new System.Drawing.Size(474, 25);
+            configComboBox.TabIndex = 3;
+            configComboBox.Visible = false;
+            // 
+            // contentPanel
+            // 
+            contentPanel.Controls.Add(previewBox);
+            contentPanel.Controls.Add(parametersPanel);
+            contentPanel.Dock = System.Windows.Forms.DockStyle.Fill;
+            contentPanel.Location = new System.Drawing.Point(9, 110);
+            contentPanel.Name = "contentPanel";
+            contentPanel.Size = new System.Drawing.Size(578, 363);
+            contentPanel.TabIndex = 1;
+            // 
+            // previewBox
+            // 
+            previewBox.ActiveWorkArea = null;
+            previewBox.AllowPan = false;
+            previewBox.AllowSelect = false;
+            previewBox.AllowZoom = false;
+            previewBox.BackColor = System.Drawing.Color.White;
+            colorScheme1.BackgroundColor = System.Drawing.Color.DarkGray;
+            colorScheme1.BoundingBoxColor = System.Drawing.Color.FromArgb(128, 128, 255);
+            colorScheme1.EdgeSpacingColor = System.Drawing.Color.FromArgb(180, 180, 180);
+            colorScheme1.LayoutFillColor = System.Drawing.Color.WhiteSmoke;
+            colorScheme1.LayoutOutlineColor = System.Drawing.Color.Gray;
+            colorScheme1.OriginColor = System.Drawing.Color.Gray;
+            colorScheme1.PreviewPartColor = System.Drawing.Color.FromArgb(255, 140, 0);
+            colorScheme1.RapidColor = System.Drawing.Color.DodgerBlue;
+            previewBox.ColorScheme = colorScheme1;
+            cutOffSettings1.CutDirection = CutDirection.AwayFromOrigin;
+            cutOffSettings1.MinSegmentLength = 0.05D;
+            cutOffSettings1.Overtravel = 0D;
+            cutOffSettings1.PartClearance = 0.02D;
+            previewBox.CutOffSettings = cutOffSettings1;
+            previewBox.DebugRemnantPriorities = null;
+            previewBox.DebugRemnants = null;
+            previewBox.Dock = System.Windows.Forms.DockStyle.Fill;
+            previewBox.DrawBounds = false;
+            previewBox.DrawCutDirection = false;
+            previewBox.DrawOffset = false;
+            previewBox.DrawOrigin = false;
+            previewBox.DrawPiercePoints = false;
+            previewBox.DrawRapid = false;
+            previewBox.FillParts = true;
+            previewBox.Location = new System.Drawing.Point(0, 0);
+            previewBox.Name = "previewBox";
+            previewBox.OffsetIncrementDistance = 10D;
+            previewBox.OffsetTolerance = 0.001D;
+            plate1.CutOffs = observableList_11;
+            plate1.CuttingParameters = null;
+            plate1.GrainAngle = 0D;
+            plate1.Parts = observableList_12;
+            plate1.PartSpacing = 0D;
+            plate1.Quadrant = 1;
+            plate1.Quantity = 0;
+            previewBox.Plate = plate1;
+            previewBox.RotateIncrementAngle = 10D;
+            previewBox.ShowBendLines = false;
+            previewBox.Size = new System.Drawing.Size(318, 363);
+            previewBox.Status = "Select";
+            previewBox.TabIndex = 4;
+            previewBox.TabStop = false;
+            // 
+            // parametersPanel
+            // 
+            parametersPanel.AutoScroll = true;
+            parametersPanel.Dock = System.Windows.Forms.DockStyle.Right;
+            parametersPanel.Location = new System.Drawing.Point(318, 0);
+            parametersPanel.Name = "parametersPanel";
+            parametersPanel.Padding = new System.Windows.Forms.Padding(8, 0, 0, 0);
+            parametersPanel.Size = new System.Drawing.Size(260, 363);
+            parametersPanel.TabIndex = 5;
+            // 
+            // buttonPanel
+            // 
+            buttonPanel.Controls.Add(addButton);
+            buttonPanel.Controls.Add(closeButton);
+            buttonPanel.Dock = System.Windows.Forms.DockStyle.Fill;
+            buttonPanel.Location = new System.Drawing.Point(9, 479);
+            buttonPanel.Name = "buttonPanel";
+            buttonPanel.Size = new System.Drawing.Size(578, 38);
+            buttonPanel.TabIndex = 2;
+            // 
+            // addButton
+            // 
+            addButton.Anchor = System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right;
+            addButton.Location = new System.Drawing.Point(379, 5);
+            addButton.Name = "addButton";
+            addButton.Size = new System.Drawing.Size(100, 30);
+            addButton.TabIndex = 0;
+            addButton.Text = "Add to Nest";
+            addButton.UseVisualStyleBackColor = true;
+            // 
+            // closeButton
+            // 
+            closeButton.Anchor = System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right;
+            closeButton.DialogResult = System.Windows.Forms.DialogResult.Cancel;
+            closeButton.Location = new System.Drawing.Point(485, 5);
+            closeButton.Name = "closeButton";
+            closeButton.Size = new System.Drawing.Size(90, 30);
+            closeButton.TabIndex = 1;
+            closeButton.Text = "Close";
+            closeButton.UseVisualStyleBackColor = true;
+            // 
+            // ShapeLibraryForm
+            // 
+            AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
+            CancelButton = closeButton;
+            ClientSize = new System.Drawing.Size(750, 520);
+            Controls.Add(splitContainer);
+            Font = new System.Drawing.Font("Segoe UI", 9.75F);
+            MinimizeBox = false;
+            MinimumSize = new System.Drawing.Size(600, 400);
+            Name = "ShapeLibraryForm";
+            ShowIcon = false;
+            ShowInTaskbar = false;
+            StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
+            Text = "Shape Library";
+            splitContainer.Panel1.ResumeLayout(false);
+            splitContainer.Panel2.ResumeLayout(false);
+            ((System.ComponentModel.ISupportInitialize)splitContainer).EndInit();
+            splitContainer.ResumeLayout(false);
+            layoutTable.ResumeLayout(false);
+            layoutTable.PerformLayout();
+            fieldsTable.ResumeLayout(false);
+            fieldsTable.PerformLayout();
+            ((System.ComponentModel.ISupportInitialize)quantityUpDown).EndInit();
+            contentPanel.ResumeLayout(false);
+            buttonPanel.ResumeLayout(false);
+            ResumeLayout(false);
+        }
+
+        #endregion
+
+        private System.Windows.Forms.SplitContainer splitContainer;
+        private System.Windows.Forms.ListBox shapeListBox;
+        private System.Windows.Forms.TableLayoutPanel layoutTable;
+        private System.Windows.Forms.TableLayoutPanel fieldsTable;
+        private System.Windows.Forms.Label nameLabel;
+        private System.Windows.Forms.TextBox nameTextBox;
+        private System.Windows.Forms.Label qtyLabel;
+        private Controls.NumericUpDown quantityUpDown;
+        private System.Windows.Forms.Label configLabel;
+        private System.Windows.Forms.ComboBox configComboBox;
+        private System.Windows.Forms.Panel contentPanel;
+        private Controls.ShapePreviewControl previewBox;
+        private System.Windows.Forms.Panel parametersPanel;
+        private System.Windows.Forms.Panel buttonPanel;
+        private System.Windows.Forms.Button addButton;
+        private System.Windows.Forms.Button closeButton;
+    }
+}

OpenNest/Forms/ShapeLibraryForm.cs

@@ -0,0 +1,322 @@
+using OpenNest.Shapes;
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using System.Windows.Forms;
+
+namespace OpenNest.Forms
+{
+    public partial class ShapeLibraryForm : Form
+    {
+        private static readonly JsonSerializerOptions JsonOptions = new JsonSerializerOptions
+        {
+            PropertyNameCaseInsensitive = true
+        };
+
+        private readonly List<Drawing> addedDrawings = new List<Drawing>();
+        private readonly List<ShapeEntry> shapeEntries = new List<ShapeEntry>();
+        private readonly List<ParameterBinding> parameterBindings = new List<ParameterBinding>();
+
+        private ShapeEntry selectedEntry;
+        private bool suppressPreview;
+
+        public ShapeLibraryForm()
+        {
+            InitializeComponent();
+            DiscoverShapes();
+            PopulateShapeList();
+
+            shapeListBox.DrawItem += ShapeListBox_DrawItem;
+            shapeListBox.SelectedIndexChanged += ShapeListBox_SelectedIndexChanged;
+            configComboBox.SelectedIndexChanged += ConfigComboBox_SelectedIndexChanged;
+            addButton.Click += AddButton_Click;
+            closeButton.Click += (s, e) => Close();
+
+            if (shapeListBox.Items.Count > 0)
+                shapeListBox.SelectedIndex = 0;
+        }
+
+        public List<Drawing> GetDrawings() => addedDrawings;
+
+        private void DiscoverShapes()
+        {
+            var baseType = typeof(ShapeDefinition);
+            var shapeTypes = baseType.Assembly.GetTypes()
+                .Where(t => t.IsClass && !t.IsAbstract && baseType.IsAssignableFrom(t))
+                .OrderBy(t => t.Name)
+                .ToList();
+
+            var configDir = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Configurations");
+
+            foreach (var type in shapeTypes)
+            {
+                var entry = new ShapeEntry { ShapeType = type };
+                entry.DisplayName = FriendlyName(type.Name);
+
+                var configPath = Path.Combine(configDir, type.Name + ".json");
+                if (File.Exists(configPath))
+                    entry.Configurations = LoadConfigurations(type, configPath);
+
+                shapeEntries.Add(entry);
+            }
+        }
+
+        private List<ShapeDefinition> LoadConfigurations(Type shapeType, string path)
+        {
+            try
+            {
+                var json = File.ReadAllText(path);
+                var listType = typeof(List<>).MakeGenericType(shapeType);
+                var list = JsonSerializer.Deserialize(json, listType, JsonOptions);
+                return ((System.Collections.IEnumerable)list).Cast<ShapeDefinition>().ToList();
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        private void PopulateShapeList()
+        {
+            foreach (var entry in shapeEntries)
+                shapeListBox.Items.Add(entry);
+        }
+
+        private void ShapeListBox_DrawItem(object sender, DrawItemEventArgs e)
+        {
+            if (e.Index < 0) return;
+
+            e.DrawBackground();
+
+            var entry = (ShapeEntry)shapeListBox.Items[e.Index];
+            var textColor = (e.State & DrawItemState.Selected) != 0
+                ? SystemColors.HighlightText
+                : SystemColors.ControlText;
+
+            var text = entry.DisplayName;
+            if (entry.HasConfigurations)
+                text += $"  ({entry.Configurations.Count})";
+
+            using (var brush = new SolidBrush(textColor))
+            {
+                var format = new StringFormat { LineAlignment = StringAlignment.Center };
+                var rect = new RectangleF(8, e.Bounds.Y, e.Bounds.Width - 8, e.Bounds.Height);
+                e.Graphics.DrawString(text, e.Font, brush, rect, format);
+            }
+
+            e.DrawFocusRectangle();
+        }
+
+        private void ShapeListBox_SelectedIndexChanged(object sender, EventArgs e)
+        {
+            if (shapeListBox.SelectedIndex < 0) return;
+
+            selectedEntry = (ShapeEntry)shapeListBox.SelectedItem;
+            suppressPreview = true;
+
+            var hasConfigs = selectedEntry.HasConfigurations;
+            configLabel.Visible = hasConfigs;
+            configComboBox.Visible = hasConfigs;
+
+            if (hasConfigs)
+            {
+                configComboBox.Items.Clear();
+                foreach (var cfg in selectedEntry.Configurations)
+                    configComboBox.Items.Add(cfg.Name);
+
+                configComboBox.SelectedIndex = 0;
+            }
+            else
+            {
+                nameTextBox.Text = selectedEntry.DisplayName;
+                var defaults = (ShapeDefinition)Activator.CreateInstance(selectedEntry.ShapeType);
+                defaults.SetPreviewDefaults();
+                BuildParameterControls(selectedEntry.ShapeType, defaults);
+            }
+
+            suppressPreview = false;
+            UpdatePreview();
+        }
+
+        private void ConfigComboBox_SelectedIndexChanged(object sender, EventArgs e)
+        {
+            if (configComboBox.SelectedIndex < 0 || selectedEntry == null) return;
+
+            var config = selectedEntry.Configurations[configComboBox.SelectedIndex];
+            nameTextBox.Text = config.Name;
+
+            suppressPreview = true;
+            BuildParameterControls(selectedEntry.ShapeType, config);
+            suppressPreview = false;
+            UpdatePreview();
+        }
+
+        private void BuildParameterControls(Type shapeType, ShapeDefinition sourceValues)
+        {
+            parametersPanel.SuspendLayout();
+            parametersPanel.Controls.Clear();
+            parameterBindings.Clear();
+
+            var props = shapeType.GetProperties(BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly)
+                .Where(p => p.CanRead && p.CanWrite && p.Name != "Name")
+                .ToArray();
+
+            var panelWidth = parametersPanel.ClientSize.Width - parametersPanel.Padding.Horizontal;
+            var y = 4;
+
+            foreach (var prop in props)
+            {
+                var label = new Label
+                {
+                    Text = FriendlyName(prop.Name),
+                    Location = new Point(parametersPanel.Padding.Left, y),
+                    AutoSize = true
+                };
+
+                y += 18;
+
+                var tb = new TextBox
+                {
+                    Location = new Point(parametersPanel.Padding.Left, y),
+                    Width = panelWidth,
+                    Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right
+                };
+
+                if (sourceValues != null)
+                {
+                    if (prop.PropertyType == typeof(int))
+                        tb.Text = ((int)prop.GetValue(sourceValues)).ToString();
+                    else
+                        tb.Text = ((double)prop.GetValue(sourceValues)).ToString("G");
+                }
+
+                tb.TextChanged += (s, ev) => UpdatePreview();
+
+                parameterBindings.Add(new ParameterBinding { Property = prop, Control = tb });
+
+                parametersPanel.Controls.Add(label);
+                parametersPanel.Controls.Add(tb);
+
+                y += 30;
+            }
+
+            parametersPanel.ResumeLayout(true);
+        }
+
+        private void UpdatePreview()
+        {
+            if (suppressPreview || selectedEntry == null) return;
+
+            try
+            {
+                var shape = CreateShapeFromInputs();
+                if (shape == null) return;
+
+                var drawing = shape.GetDrawing();
+                previewBox.ShowDrawing(drawing);
+
+                if (drawing?.Program != null)
+                {
+                    var bb = drawing.Program.BoundingBox();
+                    previewBox.SetInfo(
+                        nameTextBox.Text,
+                        string.Format("{0:F3} x {1:F3}", bb.Size.Length, bb.Size.Width));
+                }
+            }
+            catch
+            {
+                previewBox.ShowDrawing(null);
+            }
+        }
+
+        private ShapeDefinition CreateShapeFromInputs()
+        {
+            var shape = (ShapeDefinition)Activator.CreateInstance(selectedEntry.ShapeType);
+            shape.Name = nameTextBox.Text;
+
+            foreach (var binding in parameterBindings)
+            {
+                var tb = (TextBox)binding.Control;
+
+                if (binding.Property.PropertyType == typeof(int))
+                {
+                    if (int.TryParse(tb.Text, out var intVal))
+                    {
+                        binding.Property.SetValue(shape, intVal);
+                        tb.ForeColor = SystemColors.WindowText;
+                    }
+                    else
+                    {
+                        tb.ForeColor = Color.Red;
+                        return null;
+                    }
+                }
+                else
+                {
+                    var val = ArchUnits.GetLengthInches(tb);
+                    if (double.IsNaN(val))
+                        return null;
+
+                    binding.Property.SetValue(shape, val);
+                }
+            }
+
+            return shape;
+        }
+
+        private void AddButton_Click(object sender, EventArgs e)
+        {
+            try
+            {
+                var shape = CreateShapeFromInputs();
+                if (shape == null) return;
+
+                var drawing = shape.GetDrawing();
+                drawing.Color = Drawing.GetNextColor();
+                drawing.Quantity.Required = (int)quantityUpDown.Value;
+
+                addedDrawings.Add(drawing);
+                DialogResult = DialogResult.OK;
+
+                addButton.Text = $"Added ({addedDrawings.Count})";
+            }
+            catch (Exception ex)
+            {
+                MessageBox.Show(
+                    $"Failed to create shape: {ex.Message}",
+                    "Error",
+                    MessageBoxButtons.OK,
+                    MessageBoxIcon.Warning);
+            }
+        }
+
+        private static string FriendlyName(string name)
+        {
+            if (name.EndsWith("Shape"))
+                name = name.Substring(0, name.Length - 5);
+
+            return Regex.Replace(name, @"(?<=[a-z0-9])([A-Z])", " $1");
+        }
+
+        private class ShapeEntry
+        {
+            public Type ShapeType { get; set; }
+            public string DisplayName { get; set; }
+            public List<ShapeDefinition> Configurations { get; set; }
+            public bool HasConfigurations => Configurations != null && Configurations.Count > 0;
+
+            public override string ToString() => DisplayName;
+        }
+
+        private class ParameterBinding
+        {
+            public PropertyInfo Property { get; set; }
+            public Control Control { get; set; }
+        }
+    }
+}

OpenNest/Forms/ShapeLibraryForm.resx

@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!--
+    Microsoft ResX Schema
+
+    Version 2.0
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
+    associated with the data types.
+
+    Example:
+
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+
+    There are any number of "resheader" rows that contain simple
+    name/value pairs.
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
+    mimetype set.
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
+    extensible. For a given mimetype the value must be set accordingly:
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
+    read any of the formats listed below.
+
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>