fix(core): arc bounding box inflated for near-zero sweep arcs

Arcs with sweep angles smaller than Tolerance.Epsilon were treated as
full circles by IsBetweenRad's shortcut check, causing UpdateBounds to
expand the bounding box to Center ± Radius. This made zoom-to-fit zoom
out far beyond the actual part extents.

Skip cardinal angle expansion when sweep is near-zero so the bounding
box uses only the arc's start/end points.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

OpenNest.Console/Program.cs

@@ -41,6 +41,7 @@ static class NestConsole
             }
         }
 
+        using var log = SetUpLog(options);
         var nest = LoadOrCreateNest(options);
 
         if (nest == null)
@@ -67,6 +68,10 @@ static class NestConsole
 
         var overlapCount = CheckOverlaps(plate, options);
 
+        // Flush and close the log before printing results.
+        Trace.Flush();
+        log?.Dispose();
+
         PrintResults(success, plate, elapsed);
         Save(nest, options);
         PostProcess(nest, options);
@@ -107,6 +112,9 @@ static class NestConsole
                 case "--no-save":
                     o.NoSave = true;
                     break;
+                case "--no-log":
+                    o.NoLog = true;
+                    break;
                 case "--keep-parts":
                     o.KeepParts = true;
                     break;
@@ -145,14 +153,28 @@ static class NestConsole
         return o;
     }
 
+    static StreamWriter SetUpLog(Options options)
+    {
+        if (options.NoLog)
+            return null;
+
+        var baseDir = Path.GetDirectoryName(options.InputFiles[0]);
+        var logDir = Path.Combine(baseDir, "test-harness-logs");
+        Directory.CreateDirectory(logDir);
+        var logFile = Path.Combine(logDir, $"debug-{DateTime.Now:yyyyMMdd-HHmmss}.log");
+        var writer = new StreamWriter(logFile) { AutoFlush = true };
+        Trace.Listeners.Add(new TextWriterTraceListener(writer));
+        Console.WriteLine($"Debug log: {logFile}");
+        return writer;
+    }
+
     static Nest LoadOrCreateNest(Options options)
     {
         var nestFile = options.InputFiles.FirstOrDefault(f =>
             f.EndsWith(NestFormat.FileExtension, StringComparison.OrdinalIgnoreCase)
             || f.EndsWith(".zip", StringComparison.OrdinalIgnoreCase));
         var dxfFiles = options.InputFiles.Where(f =>
-            f.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase) ||
-            f.EndsWith(".dwg", StringComparison.OrdinalIgnoreCase)).ToList();
+            f.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase)).ToList();
 
         // If we have a nest file, load it and optionally add DXFs.
         if (nestFile != null)
@@ -188,7 +210,7 @@ static class NestConsole
         // DXF-only mode: create a fresh nest.
         if (dxfFiles.Count == 0)
         {
-            Console.Error.WriteLine("Error: no nest (.nest) or CAD (.dxf/.dwg) files specified");
+            Console.Error.WriteLine("Error: no nest (.nest) or DXF (.dxf) files specified");
             return null;
         }
 
@@ -462,7 +484,7 @@ static class NestConsole
         Console.Error.WriteLine("Usage: OpenNest.Console <input-files...> [options]");
         Console.Error.WriteLine();
         Console.Error.WriteLine("Arguments:");
-        Console.Error.WriteLine("  input-files            One or more .nest nest files or .dxf/.dwg drawing files");
+        Console.Error.WriteLine("  input-files            One or more .nest nest files or .dxf drawing files");
         Console.Error.WriteLine();
         Console.Error.WriteLine("Modes:");
         Console.Error.WriteLine("  <nest.nest>             Load nest and fill (existing behavior)");
@@ -481,6 +503,7 @@ static class NestConsole
         Console.Error.WriteLine("  --keep-parts           Don't clear existing parts before filling");
         Console.Error.WriteLine("  --check-overlaps       Run overlap detection after fill (exit code 1 if found)");
         Console.Error.WriteLine("  --no-save              Skip saving output file");
+        Console.Error.WriteLine("  --no-log               Skip writing debug log file");
         Console.Error.WriteLine("  --post <name>          Run a post processor after nesting");
         Console.Error.WriteLine("  --post-output <path>   Output file for post processor (default: <input>.cnc)");
         Console.Error.WriteLine("  --posts-dir <path>     Directory containing post processor DLLs (default: Posts/)");
@@ -499,6 +522,7 @@ static class NestConsole
         public Size? PlateSize;
         public bool CheckOverlaps;
         public bool NoSave;
+        public bool NoLog;
         public bool KeepParts;
         public bool AutoNest;
         public string TemplateFile;

OpenNest.Core/Converters/ConvertGeometry.cs

@@ -1,6 +1,5 @@
 using OpenNest.CNC;
 using OpenNest.Geometry;
-using OpenNest.Math;
 using System.Collections.Generic;
 
 namespace OpenNest.Converters
@@ -82,21 +81,12 @@ namespace OpenNest.Converters
             var startpt = arc.StartPoint();
             var endpt = arc.EndPoint();
 
-            if (startpt.DistanceTo(lastpt) > Tolerance.ChainTolerance)
+            if (startpt != lastpt)
                 pgm.MoveTo(startpt);
 
             lastpt = endpt;
 
-            var sweep = System.Math.Abs(arc.SweepAngle());
-            if (sweep < Tolerance.Epsilon || sweep.IsEqualTo(Angle.TwoPI))
-            {
-                pgm.LineTo(endpt);
-            }
-            else
-            {
             pgm.ArcTo(endpt, arc.Center, arc.IsReversed ? RotationType.CW : RotationType.CCW);
-            }
-
             return lastpt;
         }
 
@@ -104,7 +94,7 @@ namespace OpenNest.Converters
         {
             var startpt = new Vector(circle.Center.X + circle.Radius, circle.Center.Y);
 
-            if (startpt.DistanceTo(lastpt) > Tolerance.ChainTolerance)
+            if (startpt != lastpt)
                 pgm.MoveTo(startpt);
 
             pgm.ArcTo(startpt, circle.Center, circle.Rotation);
@@ -115,7 +105,7 @@ namespace OpenNest.Converters
 
         private static Vector AddLine(Program pgm, Vector lastpt, Line line)
         {
-            if (line.StartPoint.DistanceTo(lastpt) > Tolerance.ChainTolerance)
+            if (line.StartPoint != lastpt)
                 pgm.MoveTo(line.StartPoint);
 
             var move = new LinearMove(line.EndPoint);

OpenNest.Core/Geometry/Box.cs

@@ -1,9 +1,8 @@
-using System;
-using OpenNest.Math;
+using OpenNest.Math;
 
 namespace OpenNest.Geometry
 {
-    public class Box : IComparable<Box>
+    public class Box
     {
         public static readonly Box Empty = new Box();
 
@@ -215,19 +214,5 @@ namespace OpenNest.Geometry
         {
             return string.Format("[Box: X={0}, Y={1}, Width={2}, Length={3}]", X, Y, Width, Length);
         }
-
-        public int CompareTo(Box other)
-        {
-            var cmp = Width.CompareTo(other.Width);
-            return cmp != 0 ? cmp : Length.CompareTo(other.Length);
-        }
-
-        public static bool operator >(Box a, Box b) => a.CompareTo(b) > 0;
-
-        public static bool operator <(Box a, Box b) => a.CompareTo(b) < 0;
-
-        public static bool operator >=(Box a, Box b) => a.CompareTo(b) >= 0;
-
-        public static bool operator <=(Box a, Box b) => a.CompareTo(b) <= 0;
     }
 }

OpenNest.Core/Geometry/EllipseConverter.cs

@@ -173,11 +173,7 @@ namespace OpenNest.Geometry
 
             if (maxDev <= tolerance)
             {
-                var arc = CreateArc(arcCenter, radius, center, semiMajor, semiMinor, rotation, t0, t1);
-                if (arc.SweepAngle() < Tolerance.Epsilon)
-                    results.Add(new Line(p0, p1));
-                else
-                    results.Add(arc);
+                results.Add(CreateArc(arcCenter, radius, center, semiMajor, semiMinor, rotation, t0, t1));
             }
             else
             {

OpenNest.Core/Geometry/ShapeBuilder.cs

@@ -1,13 +1,12 @@
 using OpenNest.Math;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 
 namespace OpenNest.Geometry
 {
     public static class ShapeBuilder
     {
-        public static List<Shape> GetShapes(IEnumerable<Entity> entities, double? weldTolerance = null)
+        public static List<Shape> GetShapes(IEnumerable<Entity> entities)
         {
             var lines = new List<Line>();
             var arcs = new List<Arc>();
@@ -58,9 +57,6 @@ namespace OpenNest.Geometry
             entityList.AddRange(lines);
             entityList.AddRange(arcs);
 
-            if (weldTolerance.HasValue)
-                WeldEndpoints(entityList, weldTolerance.Value);
-
             while (entityList.Count > 0)
             {
                 var next = entityList[0];
@@ -111,93 +107,6 @@ namespace OpenNest.Geometry
             return shapes;
         }
 
-        public static void WeldEndpoints(List<Entity> entities, double tolerance)
-        {
-            var endpointGroups = new List<List<(Entity entity, bool isStart, Vector point)>>();
-
-            foreach (var entity in entities)
-            {
-                var (start, end) = GetEndpoints(entity);
-                if (!start.IsValid() || !end.IsValid())
-                    continue;
-
-                AddToGroup(endpointGroups, entity, true, start, tolerance);
-                AddToGroup(endpointGroups, entity, false, end, tolerance);
-            }
-
-            foreach (var group in endpointGroups)
-            {
-                if (group.Count <= 1)
-                    continue;
-
-                var avgX = group.Average(g => g.point.X);
-                var avgY = group.Average(g => g.point.Y);
-                var weldedPoint = new Vector(avgX, avgY);
-
-                foreach (var (entity, isStart, _) in group)
-                    ApplyWeld(entity, isStart, weldedPoint);
-            }
-        }
-
-        private static void AddToGroup(
-            List<List<(Entity entity, bool isStart, Vector point)>> groups,
-            Entity entity, bool isStart, Vector point, double tolerance)
-        {
-            foreach (var group in groups)
-            {
-                if (group[0].point.DistanceTo(point) <= tolerance)
-                {
-                    group.Add((entity, isStart, point));
-                    return;
-                }
-            }
-
-            groups.Add(new List<(Entity, bool, Vector)> { (entity, isStart, point) });
-        }
-
-        private static (Vector start, Vector end) GetEndpoints(Entity entity)
-        {
-            switch (entity.Type)
-            {
-                case EntityType.Arc:
-                    var arc = (Arc)entity;
-                    return (arc.StartPoint(), arc.EndPoint());
-
-                case EntityType.Line:
-                    var line = (Line)entity;
-                    return (line.StartPoint, line.EndPoint);
-
-                default:
-                    return (Vector.Invalid, Vector.Invalid);
-            }
-        }
-
-        private static void ApplyWeld(Entity entity, bool isStart, Vector weldedPoint)
-        {
-            switch (entity.Type)
-            {
-                case EntityType.Line:
-                    var line = (Line)entity;
-                    if (isStart)
-                        line.StartPoint = weldedPoint;
-                    else
-                        line.EndPoint = weldedPoint;
-                    break;
-
-                case EntityType.Arc:
-                    var arc = (Arc)entity;
-                    var deltaX = weldedPoint.X - arc.Center.X;
-                    var deltaY = weldedPoint.Y - arc.Center.Y;
-                    var angle = System.Math.Atan2(deltaY, deltaX);
-
-                    if (isStart)
-                        arc.StartAngle = angle;
-                    else
-                        arc.EndAngle = angle;
-                    break;
-            }
-        }
-
         internal static Entity GetConnected(Vector pt, IEnumerable<Entity> geometry)
         {
             var tol = Tolerance.ChainTolerance;

OpenNest.Engine/BestFit/NfpSlideStrategy.cs

@@ -1,10 +1,18 @@
 using OpenNest.Geometry;
+using OpenNest.Math;
 using System.Collections.Generic;
+using System.IO;
 
 namespace OpenNest.Engine.BestFit
 {
     public class NfpSlideStrategy : IBestFitStrategy
     {
+        private static readonly string LogPath = Path.Combine(
+            System.Environment.GetFolderPath(System.Environment.SpecialFolder.Desktop),
+            "nfp-slide-debug.log");
+
+        private static readonly object LogLock = new object();
+
         private readonly double _part2Rotation;
         private readonly Polygon _stationaryPerimeter;
         private readonly Polygon _stationaryHull;
@@ -38,6 +46,12 @@ namespace OpenNest.Engine.BestFit
 
             var hull = ConvexHull.Compute(result.Polygon.Vertices);
 
+            Log($"=== Create: drawing={drawing.Name}, rotation={Angle.ToDegrees(part2Rotation):F1}deg ===");
+            Log($"  Perimeter: {result.Polygon.Vertices.Count} verts, bounds={FormatBounds(result.Polygon)}");
+            Log($"  Hull: {hull.Vertices.Count} verts, bounds={FormatBounds(hull)}");
+            Log($"  Correction: ({result.Correction.X:F4}, {result.Correction.Y:F4})");
+            Log($"  ProgramBBox: {drawing.Program.BoundingBox()}");
+
             return new NfpSlideStrategy(part2Rotation, type, description,
                 result.Polygon, hull, result.Correction);
         }
@@ -49,17 +63,40 @@ namespace OpenNest.Engine.BestFit
             if (stepSize <= 0)
                 return candidates;
 
+            Log($"--- GenerateCandidates: drawing={drawing.Name}, part2Rot={Angle.ToDegrees(_part2Rotation):F1}deg, spacing={spacing}, stepSize={stepSize} ---");
+
+            // Orbiting polygon: same shape rotated to Part2's angle.
             var orbitingPerimeter = PolygonHelper.RotatePolygon(_stationaryPerimeter, _part2Rotation, reNormalize: true);
             var orbitingPoly = ConvexHull.Compute(orbitingPerimeter.Vertices);
 
+            Log($"  Stationary hull: {_stationaryHull.Vertices.Count} verts, bounds={FormatBounds(_stationaryHull)}");
+            Log($"  Orbiting perimeter (rotated): {orbitingPerimeter.Vertices.Count} verts, bounds={FormatBounds(orbitingPerimeter)}");
+            Log($"  Orbiting hull: {orbitingPoly.Vertices.Count} verts, bounds={FormatBounds(orbitingPoly)}");
+
             var nfp = NoFitPolygon.ComputeConvex(_stationaryHull, orbitingPoly);
 
             if (nfp == null || nfp.Vertices.Count < 3)
+            {
+                Log($"  NFP failed or degenerate (verts={nfp?.Vertices.Count ?? 0})");
                 return candidates;
+            }
 
             var verts = nfp.Vertices;
             var vertCount = nfp.IsClosed() ? verts.Count - 1 : verts.Count;
 
+            Log($"  NFP: {verts.Count} verts (closed={nfp.IsClosed()}, walking {vertCount}), bounds={FormatBounds(nfp)}");
+            Log($"  Correction: ({_correction.X:F4}, {_correction.Y:F4})");
+
+            // Log NFP vertices
+            for (var v = 0; v < vertCount; v++)
+                Log($"    NFP vert[{v}]: ({verts[v].X:F4}, {verts[v].Y:F4}) -> corrected: ({verts[v].X - _correction.X:F4}, {verts[v].Y - _correction.Y:F4})");
+
+            // Compare with what RotationSlideStrategy would produce
+            var part1 = Part.CreateAtOrigin(drawing);
+            var part2 = Part.CreateAtOrigin(drawing, _part2Rotation);
+            Log($"  Part1 (rot=0): loc=({part1.Location.X:F4}, {part1.Location.Y:F4}), bbox={part1.BoundingBox}");
+            Log($"  Part2 (rot={Angle.ToDegrees(_part2Rotation):F1}): loc=({part2.Location.X:F4}, {part2.Location.Y:F4}), bbox={part2.BoundingBox}");
+
             var testNumber = 0;
 
             for (var i = 0; i < vertCount; i++)
@@ -88,6 +125,20 @@ namespace OpenNest.Engine.BestFit
                 }
             }
 
+            // Log overlap check for vertex candidates (first few)
+            var checkCount = System.Math.Min(vertCount, 8);
+            for (var c = 0; c < checkCount; c++)
+            {
+                var cand = candidates[c];
+                var p2 = Part.CreateAtOrigin(drawing, cand.Part2Rotation);
+                p2.Location = cand.Part2Offset;
+                var overlaps = part1.Intersects(p2, out _);
+                Log($"  Candidate[{c}]: offset=({cand.Part2Offset.X:F4}, {cand.Part2Offset.Y:F4}), overlaps={overlaps}");
+            }
+
+            Log($"  Total candidates: {candidates.Count}");
+            Log("");
+
             return candidates;
         }
 
@@ -109,5 +160,20 @@ namespace OpenNest.Engine.BestFit
                 Spacing = spacing
             };
         }
+
+        private static string FormatBounds(Polygon polygon)
+        {
+            polygon.UpdateBounds();
+            var bb = polygon.BoundingBox;
+            return $"[({bb.Left:F4}, {bb.Bottom:F4})-({bb.Right:F4}, {bb.Top:F4}), {bb.Width:F2}x{bb.Length:F2}]";
+        }
+
+        private static void Log(string message)
+        {
+            lock (LogLock)
+            {
+                File.AppendAllText(LogPath, message + "\n");
+            }
+        }
     }
 }

OpenNest.Engine/Fill/FillLinear.cs

@@ -62,90 +62,91 @@ namespace OpenNest.Engine.Fill
         }
 
         /// <summary>
-        /// Finds the geometry-aware copy distance between two identical parts along an axis.
-        /// Uses native Line/Arc entities (inflated by half-spacing) so curves are handled
-        /// exactly without polygon sampling error.
+        /// Computes the slide distance for the push algorithm, returning the
+        /// geometry-aware copy distance along the given axis.
         /// </summary>
-        private double FindCopyDistance(Part partA, NestDirection direction)
+        private double ComputeCopyDistance(double bboxDim, double slideDistance)
         {
-            var bboxDim = GetDimension(partA.BoundingBox, direction);
-            var pushDir = GetPushDirection(direction);
-            var startOffset = bboxDim + PartSpacing + Tolerance.Epsilon;
-            var offset = MakeOffset(direction, startOffset);
-
-            var stationaryEntities = PartGeometry.GetOffsetPerimeterEntities(partA, HalfSpacing);
-            var movingEntities = PartGeometry.GetOffsetPerimeterEntities(
-                partA.CloneAtOffset(offset), HalfSpacing);
-
-            var slideDistance = SpatialQuery.DirectionalDistance(
-                movingEntities, stationaryEntities, pushDir);
-
             if (slideDistance >= double.MaxValue || slideDistance < 0)
                 return bboxDim + PartSpacing;
 
-            return startOffset - slideDistance;
+            // The geometry-aware slide can produce a copy distance smaller than
+            // the part itself when inflated corner/arc vertices interact spuriously.
+            // Clamp to bboxDim + PartSpacing to prevent bounding box overlap.
+            return System.Math.Max(bboxDim - slideDistance, bboxDim + PartSpacing);
+        }
+
+        /// <summary>
+        /// Finds the geometry-aware copy distance between two identical parts along an axis.
+        /// Both parts are inflated by half-spacing for symmetric spacing.
+        /// </summary>
+        private double FindCopyDistance(Part partA, NestDirection direction, PartBoundary boundary)
+        {
+            var bboxDim = GetDimension(partA.BoundingBox, direction);
+            var pushDir = GetPushDirection(direction);
+
+            var locationBOffset = MakeOffset(direction, bboxDim);
+
+            // Use the most efficient array-based overload to avoid all allocations.
+            var slideDistance = SpatialQuery.DirectionalDistance(
+                boundary.GetEdges(pushDir), partA.Location + locationBOffset,
+                boundary.GetEdges(SpatialQuery.OppositeDirection(pushDir)), partA.Location,
+                pushDir);
+
+            return ComputeCopyDistance(bboxDim, slideDistance);
         }
 
         /// <summary>
         /// Finds the geometry-aware copy distance between two identical patterns along an axis.
-        /// Checks every pair of parts across adjacent pattern copies so multi-part patterns
-        /// (e.g. interlocking pairs) maintain spacing between ALL parts. Uses native entity
-        /// geometry inflated by half-spacing — same primitive the Compactor uses — so arcs
-        /// are exact and no bbox clamp is needed.
+        /// Checks every pair of parts across adjacent patterns so that multi-part
+        /// patterns (e.g. interlocking pairs) maintain spacing between ALL parts.
+        /// Both sides are inflated by half-spacing for symmetric spacing.
         /// </summary>
-        private double FindPatternCopyDistance(Pattern patternA, NestDirection direction)
+        private double FindPatternCopyDistance(Pattern patternA, NestDirection direction, PartBoundary[] boundaries)
         {
-            if (patternA.Parts.Count == 1)
-                return FindCopyDistance(patternA.Parts[0], direction);
+            if (patternA.Parts.Count <= 1)
+                return FindSinglePartPatternCopyDistance(patternA, direction, boundaries[0]);
 
             var bboxDim = GetDimension(patternA.BoundingBox, direction);
             var pushDir = GetPushDirection(direction);
             var opposite = SpatialQuery.OppositeDirection(pushDir);
-            var dirVec = SpatialQuery.DirectionToOffset(pushDir, 1.0);
 
             // bboxDim already spans max(upper) - min(lower) across all parts,
             // so the start offset just needs to push beyond that plus spacing.
             var startOffset = bboxDim + PartSpacing + Tolerance.Epsilon;
             var offset = MakeOffset(direction, startOffset);
 
-            var parts = patternA.Parts;
-            var stationaryBoxes = new Box[parts.Count];
-            var movingBoxes = new Box[parts.Count];
-            var stationaryEntities = new List<Entity>[parts.Count];
-            var movingEntities = new List<Entity>[parts.Count];
+            var maxCopyDistance = FindMaxPairDistance(
+                patternA.Parts, boundaries, offset, pushDir, opposite, startOffset);
 
-            for (var i = 0; i < parts.Count; i++)
-            {
-                stationaryBoxes[i] = parts[i].BoundingBox;
-                movingBoxes[i] = stationaryBoxes[i].Translate(offset);
+            // The copy distance must be at least bboxDim + PartSpacing to prevent
+            // bounding box overlap. Cross-pair slides can underestimate when the
+            // circumscribed polygon boundary overshoots the true arc, creating
+            // spurious contacts between diagonal parts in adjacent copies.
+            return System.Math.Max(maxCopyDistance, bboxDim + PartSpacing);
         }
 
+        /// <summary>
+        /// Tests every pair of parts across adjacent pattern copies and returns the
+        /// maximum copy distance found. Returns 0 if no valid slide was found.
+        /// </summary>
+        private static double FindMaxPairDistance(
+            List<Part> parts, PartBoundary[] boundaries, Vector offset,
+            PushDirection pushDir, PushDirection opposite, double startOffset)
+        {
             var maxCopyDistance = 0.0;
 
             for (var j = 0; j < parts.Count; j++)
             {
-                var movingBox = movingBoxes[j];
+                var movingEdges = boundaries[j].GetEdges(pushDir);
+                var locationB = parts[j].Location + offset;
 
                 for (var i = 0; i < parts.Count; i++)
                 {
-                    var stationaryBox = stationaryBoxes[i];
-
-                    // Skip if stationary is already ahead of moving in the push direction
-                    // (sliding forward would take them further apart).
-                    if (SpatialQuery.DirectionalGap(movingBox, stationaryBox, opposite) > 0)
-                        continue;
-
-                    // Skip if bboxes can't overlap along the axis perpendicular to the push.
-                    if (!SpatialQuery.PerpendicularOverlap(movingBox, stationaryBox, dirVec))
-                        continue;
-
-                    stationaryEntities[i] ??= PartGeometry.GetOffsetPerimeterEntities(
-                        parts[i], HalfSpacing);
-                    movingEntities[j] ??= PartGeometry.GetOffsetPerimeterEntities(
-                        parts[j].CloneAtOffset(offset), HalfSpacing);
-
                     var slideDistance = SpatialQuery.DirectionalDistance(
-                        movingEntities[j], stationaryEntities[i], pushDir);
+                        movingEdges, locationB,
+                        boundaries[i].GetEdges(opposite), parts[i].Location,
+                        pushDir);
 
                     if (slideDistance >= double.MaxValue || slideDistance < 0)
                         continue;
@@ -160,15 +161,86 @@ namespace OpenNest.Engine.Fill
             return maxCopyDistance;
         }
 
+        /// <summary>
+        /// Fast path for single-part patterns — no cross-part conflicts possible.
+        /// </summary>
+        private double FindSinglePartPatternCopyDistance(Pattern patternA, NestDirection direction, PartBoundary boundary)
+        {
+            var template = patternA.Parts[0];
+            return FindCopyDistance(template, direction, boundary);
+        }
+
+        /// <summary>
+        /// Gets offset boundary lines for all parts in a pattern using a shared boundary.
+        /// </summary>
+        private static List<Line> GetPatternLines(Pattern pattern, PartBoundary boundary, PushDirection direction)
+        {
+            var lines = new List<Line>();
+
+            foreach (var part in pattern.Parts)
+                lines.AddRange(boundary.GetLines(part.Location, direction));
+
+            return lines;
+        }
+
+        /// <summary>
+        /// Gets boundary lines for all parts in a pattern, with an additional
+        /// location offset applied. Avoids cloning the pattern.
+        /// </summary>
+        private static List<Line> GetOffsetPatternLines(Pattern pattern, Vector offset, PartBoundary boundary, PushDirection direction)
+        {
+            var lines = new List<Line>();
+
+            foreach (var part in pattern.Parts)
+                lines.AddRange(boundary.GetLines(part.Location + offset, direction));
+
+            return lines;
+        }
+
+        /// <summary>
+        /// Creates boundaries for all parts in a pattern. Parts that share the same
+        /// program geometry (same drawing and rotation) reuse the same boundary instance.
+        /// </summary>
+        private PartBoundary[] CreateBoundaries(Pattern pattern)
+        {
+            var boundaries = new PartBoundary[pattern.Parts.Count];
+            var cache = new List<(Drawing drawing, double rotation, PartBoundary boundary)>();
+
+            for (var i = 0; i < pattern.Parts.Count; i++)
+            {
+                var part = pattern.Parts[i];
+                PartBoundary found = null;
+
+                foreach (var entry in cache)
+                {
+                    if (entry.drawing == part.BaseDrawing && entry.rotation.IsEqualTo(part.Rotation))
+                    {
+                        found = entry.boundary;
+                        break;
+                    }
+                }
+
+                if (found == null)
+                {
+                    found = new PartBoundary(part, HalfSpacing);
+                    cache.Add((part.BaseDrawing, part.Rotation, found));
+                }
+
+                boundaries[i] = found;
+            }
+
+            return boundaries;
+        }
+
         /// <summary>
         /// Tiles a pattern along the given axis, returning the cloned parts
         /// (does not include the original pattern's parts). For multi-part
         /// patterns, also adds individual parts from the next incomplete copy
         /// that still fit within the work area.
         /// </summary>
-        private List<Part> TilePattern(Pattern basePattern, NestDirection direction)
+        private List<Part> TilePattern(Pattern basePattern, NestDirection direction, PartBoundary[] boundaries)
         {
-            var copyDistance = FindPatternCopyDistance(basePattern, direction);
+            var copyDistance = FindPatternCopyDistance(basePattern, direction, boundaries);
 
             if (copyDistance <= 0)
                 return new List<Part>();
@@ -322,10 +394,11 @@ namespace OpenNest.Engine.Fill
         private List<Part> FillGrid(Pattern pattern, NestDirection direction)
         {
             var perpAxis = PerpendicularAxis(direction);
+            var boundaries = CreateBoundaries(pattern);
 
             // Step 1: Tile along primary axis
             var row = new List<Part>(pattern.Parts);
-            row.AddRange(TilePattern(pattern, direction));
+            row.AddRange(TilePattern(pattern, direction, boundaries));
 
             if (pattern.Parts.Count > 1 && HasOverlappingParts(row, out var a1, out var b1))
             {
@@ -337,7 +410,7 @@ namespace OpenNest.Engine.Fill
             // If primary tiling didn't produce copies, just tile along perpendicular
             if (row.Count <= pattern.Parts.Count)
             {
-                row.AddRange(TilePattern(pattern, perpAxis));
+                row.AddRange(TilePattern(pattern, perpAxis, boundaries));
 
                 if (pattern.Parts.Count > 1 && HasOverlappingParts(row, out var a2, out var b2))
                 {
@@ -354,8 +427,9 @@ namespace OpenNest.Engine.Fill
             rowPattern.Parts.AddRange(row);
             rowPattern.UpdateBounds();
 
+            var rowBoundaries = CreateBoundaries(rowPattern);
             var gridResult = new List<Part>(rowPattern.Parts);
-            gridResult.AddRange(TilePattern(rowPattern, perpAxis));
+            gridResult.AddRange(TilePattern(rowPattern, perpAxis, rowBoundaries));
 
             if (HasOverlappingParts(gridResult, out var a3, out var b3))
             {
@@ -407,8 +481,9 @@ namespace OpenNest.Engine.Fill
                 return seed;
 
             var template = seed.Parts[0];
+            var boundary = new PartBoundary(template, HalfSpacing);
 
-            var copyDistance = FindCopyDistance(template, direction);
+            var copyDistance = FindCopyDistance(template, direction, boundary);
 
             if (copyDistance <= 0)
                 return seed;

OpenNest.IO/Bom/BomAnalyzer.cs

@@ -42,11 +42,6 @@ namespace OpenNest.IO.Bom
                     var nameWithoutExt = Path.GetFileNameWithoutExtension(file);
                     dxfFiles[nameWithoutExt] = file;
                 }
-                foreach (var file in Directory.GetFiles(dxfFolder, "*.dwg"))
-                {
-                    var nameWithoutExt = Path.GetFileNameWithoutExtension(file);
-                    dxfFiles.TryAdd(nameWithoutExt, file);
-                }
             }
 
             // Partition items into: skipped, unmatched, or matched (grouped)
@@ -62,8 +57,8 @@ namespace OpenNest.IO.Bom
 
                 var lookupName = item.FileName;
 
-                if (lookupName.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase)
-                    || lookupName.EndsWith(".dwg", StringComparison.OrdinalIgnoreCase))
+                // Strip .dxf extension if the BOM includes it
+                if (lookupName.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase))
                     lookupName = Path.GetFileNameWithoutExtension(lookupName);
 
                 if (!folderExists)

OpenNest.IO/Bom/Fraction.cs

@@ -3,7 +3,7 @@ using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 
-namespace OpenNest.Math
+namespace OpenNest.IO.Bom
 {
     public static class Fraction
     {

OpenNest.IO/CadImportResult.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using ACadSharp;
 using OpenNest.Bending;
 using OpenNest.Geometry;
 
@@ -39,11 +38,5 @@ namespace OpenNest.IO
         /// Default drawing name (filename without extension, unless overridden).
         /// </summary>
         public string Name { get; set; }
-
-        /// <summary>
-        /// The raw CAD document from the source file. Available for callers
-        /// that need access to non-geometry entities (e.g., text annotations).
-        /// </summary>
-        public CadDocument Document { get; set; }
     }
 }

OpenNest.IO/CadImporter.cs

@@ -5,7 +5,6 @@ using OpenNest.Bending;
 using OpenNest.Converters;
 using OpenNest.Geometry;
 using OpenNest.IO.Bending;
-using OpenNest.Math;
 
 namespace OpenNest.IO
 {
@@ -26,8 +25,6 @@ namespace OpenNest.IO
 
             var dxf = Dxf.Import(path);
 
-            RemoveDuplicateArcs(dxf.Entities);
-
             var bends = new List<Bend>();
             if (options.DetectBends && dxf.Document != null)
             {
@@ -47,7 +44,6 @@ namespace OpenNest.IO
                 Bounds = dxf.Entities.GetBoundingBox(),
                 SourcePath = path,
                 Name = options.Name ?? Path.GetFileNameWithoutExtension(path),
-                Document = dxf.Document,
             };
         }
 
@@ -140,33 +136,5 @@ namespace OpenNest.IO
 
             return drawing;
         }
-
-        internal static void RemoveDuplicateArcs(List<Entity> entities)
-        {
-            var circles = entities.OfType<Circle>().ToList();
-            var arcs = entities.OfType<Arc>().ToList();
-            var arcsToRemove = new List<Arc>();
-
-            foreach (var arc in arcs)
-            {
-                foreach (var circle in circles)
-                {
-                    if (arc.Layer?.Name != circle.Layer?.Name)
-                        continue;
-
-                    if (!arc.Center.DistanceTo(circle.Center).IsEqualTo(0))
-                        continue;
-
-                    if (!arc.Radius.IsEqualTo(circle.Radius))
-                        continue;
-
-                    arcsToRemove.Add(arc);
-                    break;
-                }
-            }
-
-            foreach (var arc in arcsToRemove)
-                entities.Remove(arc);
-        }
     }
 }

OpenNest.IO/Dxf.cs

@@ -27,7 +27,8 @@ namespace OpenNest.IO
         /// </summary>
         public static DxfImportResult Import(string path)
         {
-            var doc = ReadDocument(path);
+            using var reader = new DxfReader(path);
+            var doc = reader.Read();
 
             return new DxfImportResult
             {
@@ -40,7 +41,8 @@ namespace OpenNest.IO
         {
             try
             {
-                var doc = ReadDocument(path);
+                using var reader = new DxfReader(path);
+                var doc = reader.Read();
                 return ConvertEntities(doc);
             }
             catch (Exception ex)
@@ -111,23 +113,6 @@ namespace OpenNest.IO
 
         #region Private
 
-        private static bool IsDwg(string path) =>
-            Path.GetExtension(path).Equals(".dwg", StringComparison.OrdinalIgnoreCase);
-
-        private static CadDocument ReadDocument(string path)
-        {
-            if (IsDwg(path))
-            {
-                using var reader = new DwgReader(path);
-                return reader.Read();
-            }
-            else
-            {
-                using var reader = new DxfReader(path);
-                return reader.Read();
-            }
-        }
-
         private static List<Entity> ConvertEntities(CadDocument doc)
         {
             var entities = new List<Entity>();

OpenNest.Tests/Engine/NestInvarianceTests.cs

@@ -1,84 +0,0 @@
-using OpenNest.CNC;
-using OpenNest.Engine;
-using OpenNest.Engine.BestFit;
-using OpenNest.Geometry;
-using OpenNest.Math;
-using System.Threading;
-
-namespace OpenNest.Tests.Engine;
-
-public class NestInvarianceTests
-{
-    private static OpenNest.CNC.Program MakeLShapedProgram()
-    {
-        // L-shape: 100x50 outer rect with a 50x30 notch removed from top-right.
-        var pgm = new OpenNest.CNC.Program();
-        pgm.Codes.Add(new RapidMove(new Vector(0, 0)));
-        pgm.Codes.Add(new LinearMove(new Vector(100, 0)));
-        pgm.Codes.Add(new LinearMove(new Vector(100, 20)));
-        pgm.Codes.Add(new LinearMove(new Vector(50, 20)));
-        pgm.Codes.Add(new LinearMove(new Vector(50, 50)));
-        pgm.Codes.Add(new LinearMove(new Vector(0, 50)));
-        pgm.Codes.Add(new LinearMove(new Vector(0, 0)));
-        return pgm;
-    }
-
-    private static Drawing MakeImportedAt(double rotation)
-    {
-        var pgm = MakeLShapedProgram();
-        if (!Tolerance.IsEqualTo(rotation, 0))
-            pgm.Rotate(rotation, pgm.BoundingBox().Center);
-        return new Drawing("L", pgm);
-    }
-
-    private static Plate MakePlate() => new Plate(new Size(500, 500))
-    {
-        Quadrant = 1,
-        PartSpacing = 2,
-    };
-
-    private static int RunFillCount(Drawing drawing, Plate plate)
-    {
-        BestFitCache.Clear();
-        var engine = new DefaultNestEngine(plate);
-        var item = new NestItem { Drawing = drawing };
-        var parts = engine.Fill(item, plate.WorkArea(), progress: null, token: CancellationToken.None);
-        return parts?.Count ?? 0;
-    }
-
-    [Theory]
-    [InlineData(0.0)]
-    [InlineData(0.3)]
-    [InlineData(0.8)]
-    [InlineData(1.2)]
-    public void Fill_SameCount_AcrossImportOrientations(double theta)
-    {
-        var baseline = RunFillCount(MakeImportedAt(0.0), MakePlate());
-        var rotated = RunFillCount(MakeImportedAt(theta), MakePlate());
-
-        // Allow +/-1 tolerance for sweep quantization edge effects near plate boundaries.
-        Assert.InRange(rotated, baseline - 1, baseline + 1);
-    }
-
-    [Fact]
-    public void Fill_PlacedPartsStayWithinWorkArea_AcrossImportOrientations()
-    {
-        var plate = MakePlate();
-        var workArea = plate.WorkArea();
-
-        foreach (var theta in new[] { 0.0, 0.3, 0.8, 1.2 })
-        {
-            BestFitCache.Clear();
-            var engine = new DefaultNestEngine(plate);
-            var item = new NestItem { Drawing = MakeImportedAt(theta) };
-            var parts = engine.Fill(item, workArea, progress: null, token: CancellationToken.None);
-
-            Assert.NotNull(parts);
-            foreach (var p in parts)
-            {
-                Assert.InRange(p.BoundingBox.Left, workArea.Left - 0.5, workArea.Right + 0.5);
-                Assert.InRange(p.BoundingBox.Bottom, workArea.Bottom - 0.5, workArea.Top + 0.5);
-            }
-        }
-    }
-}

OpenNest.Tests/Geometry/BoxComparisonTests.cs

@@ -1,97 +0,0 @@
-using System;
-using System.Collections.Generic;
-using OpenNest.Geometry;
-using Xunit;
-
-namespace OpenNest.Tests.Geometry;
-
-public class BoxComparisonTests
-{
-    [Fact]
-    public void GreaterThan_TallerBox_ReturnsTrue()
-    {
-        var tall = new Box(0, 0, 10, 20);
-        var short_ = new Box(0, 0, 10, 10);
-
-        Assert.True(tall > short_);
-        Assert.False(short_ > tall);
-    }
-
-    [Fact]
-    public void GreaterThan_SameWidthLongerBox_ReturnsTrue()
-    {
-        var longer = new Box(0, 0, 20, 10);
-        var shorter = new Box(0, 0, 10, 10);
-
-        Assert.True(longer > shorter);
-        Assert.False(shorter > longer);
-    }
-
-    [Fact]
-    public void LessThan_ShorterBox_ReturnsTrue()
-    {
-        var tall = new Box(0, 0, 10, 20);
-        var short_ = new Box(0, 0, 10, 10);
-
-        Assert.True(short_ < tall);
-        Assert.False(tall < short_);
-    }
-
-    [Fact]
-    public void GreaterThanOrEqual_EqualBoxes_ReturnsTrue()
-    {
-        var a = new Box(0, 0, 10, 20);
-        var b = new Box(0, 0, 10, 20);
-
-        Assert.True(a >= b);
-        Assert.True(b >= a);
-    }
-
-    [Fact]
-    public void LessThanOrEqual_EqualBoxes_ReturnsTrue()
-    {
-        var a = new Box(0, 0, 10, 20);
-        var b = new Box(0, 0, 10, 20);
-
-        Assert.True(a <= b);
-        Assert.True(b <= a);
-    }
-
-    [Fact]
-    public void CompareTo_TallerBox_ReturnsPositive()
-    {
-        var tall = new Box(0, 0, 10, 20);
-        var short_ = new Box(0, 0, 10, 10);
-
-        Assert.True(tall.CompareTo(short_) > 0);
-        Assert.True(short_.CompareTo(tall) < 0);
-    }
-
-    [Fact]
-    public void CompareTo_EqualBoxes_ReturnsZero()
-    {
-        var a = new Box(0, 0, 10, 20);
-        var b = new Box(0, 0, 10, 20);
-
-        Assert.Equal(0, a.CompareTo(b));
-    }
-
-    [Fact]
-    public void Sort_OrdersByWidthThenLength()
-    {
-        var boxes = new List<Box>
-        {
-            new Box(0, 0, 20, 10),
-            new Box(0, 0, 5, 30),
-            new Box(0, 0, 10, 10),
-        };
-
-        boxes.Sort();
-
-        Assert.Equal(10, boxes[0].Width);
-        Assert.Equal(10, boxes[0].Length);
-        Assert.Equal(10, boxes[1].Width);
-        Assert.Equal(20, boxes[1].Length);
-        Assert.Equal(30, boxes[2].Width);
-    }
-}

OpenNest.Tests/Geometry/WeldEndpointsTests.cs

@@ -1,72 +0,0 @@
-using System.Collections.Generic;
-using OpenNest.Geometry;
-using OpenNest.Math;
-using Xunit;
-
-namespace OpenNest.Tests.Geometry;
-
-public class WeldEndpointsTests
-{
-    [Fact]
-    public void WeldEndpoints_SnapsNearbyLineEndpoints()
-    {
-        var line1 = new Line(0, 0, 10, 0);
-        var line2 = new Line(10.0000005, 0, 20, 0);
-        var entities = new List<Entity> { line1, line2 };
-
-        ShapeBuilder.WeldEndpoints(entities, 0.000001);
-
-        Assert.True(line1.EndPoint.DistanceTo(line2.StartPoint) <= Tolerance.Epsilon);
-    }
-
-    [Fact]
-    public void WeldEndpoints_SnapsArcEndpointByAdjustingAngle()
-    {
-        var line = new Line(0, 0, 10, 0);
-        var arc = new Arc(15, 0, 5, Angle.ToRadians(180.001), Angle.ToRadians(90));
-        var entities = new List<Entity> { line, arc };
-
-        ShapeBuilder.WeldEndpoints(entities, 0.01);
-
-        var arcStart = arc.StartPoint();
-        Assert.True(line.EndPoint.DistanceTo(arcStart) <= 0.01);
-    }
-
-    [Fact]
-    public void WeldEndpoints_DoesNotWeldDistantEndpoints()
-    {
-        var line1 = new Line(0, 0, 10, 0);
-        var line2 = new Line(10.1, 0, 20, 0);
-        var entities = new List<Entity> { line1, line2 };
-
-        ShapeBuilder.WeldEndpoints(entities, 0.000001);
-
-        Assert.True(line1.EndPoint.DistanceTo(line2.StartPoint) > 0.01);
-    }
-
-    [Fact]
-    public void GetShapes_WithWeldTolerance_WeldsBeforeChaining()
-    {
-        var line1 = new Line(0, 0, 10, 0);
-        var line2 = new Line(10.0000005, 0, 10.0000005, 10);
-        var entities = new List<Entity> { line1, line2 };
-
-        var shapes = ShapeBuilder.GetShapes(entities, weldTolerance: 0.000001);
-
-        Assert.Single(shapes);
-        Assert.Equal(2, shapes[0].Entities.Count);
-    }
-
-    [Fact]
-    public void GetShapes_WithoutWeldTolerance_DefaultBehavior()
-    {
-        var line1 = new Line(0, 0, 10, 0);
-        var line2 = new Line(10, 0, 10, 10);
-        var entities = new List<Entity> { line1, line2 };
-
-        var shapes = ShapeBuilder.GetShapes(entities);
-
-        Assert.Single(shapes);
-        Assert.Equal(2, shapes[0].Entities.Count);
-    }
-}

OpenNest.Tests/IO/RemoveDuplicateArcsTests.cs

@@ -1,96 +0,0 @@
-using System.Collections.Generic;
-using System.Linq;
-using OpenNest.Geometry;
-using OpenNest.IO;
-using OpenNest.Math;
-using Xunit;
-
-namespace OpenNest.Tests.IO;
-
-public class RemoveDuplicateArcsTests
-{
-    [Fact]
-    public void RemoveDuplicateArcs_RemovesArcMatchingCircle_SameLayer()
-    {
-        var layer = new Layer("0");
-        var circle = new Circle(10, 10, 5) { Layer = layer };
-        var arc = new Arc(10, 10, 5, 0, Angle.ToRadians(90)) { Layer = layer };
-        var line = new Line(0, 0, 10, 0) { Layer = layer };
-        var entities = new List<Entity> { circle, arc, line };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Equal(2, entities.Count);
-        Assert.Contains(circle, entities);
-        Assert.Contains(line, entities);
-        Assert.DoesNotContain(arc, entities);
-    }
-
-    [Fact]
-    public void RemoveDuplicateArcs_KeepsArcOnDifferentLayer()
-    {
-        var layer1 = new Layer("cut");
-        var layer2 = new Layer("etch");
-        var circle = new Circle(10, 10, 5) { Layer = layer1 };
-        var arc = new Arc(10, 10, 5, 0, Angle.ToRadians(90)) { Layer = layer2 };
-        var entities = new List<Entity> { circle, arc };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Equal(2, entities.Count);
-        Assert.Contains(arc, entities);
-    }
-
-    [Fact]
-    public void RemoveDuplicateArcs_KeepsArcWithDifferentRadius()
-    {
-        var layer = new Layer("0");
-        var circle = new Circle(10, 10, 5) { Layer = layer };
-        var arc = new Arc(10, 10, 3, 0, Angle.ToRadians(90)) { Layer = layer };
-        var entities = new List<Entity> { circle, arc };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Equal(2, entities.Count);
-    }
-
-    [Fact]
-    public void RemoveDuplicateArcs_KeepsArcWithDifferentCenter()
-    {
-        var layer = new Layer("0");
-        var circle = new Circle(10, 10, 5) { Layer = layer };
-        var arc = new Arc(20, 20, 5, 0, Angle.ToRadians(90)) { Layer = layer };
-        var entities = new List<Entity> { circle, arc };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Equal(2, entities.Count);
-    }
-
-    [Fact]
-    public void RemoveDuplicateArcs_NoCircles_NoChange()
-    {
-        var arc = new Arc(10, 10, 5, 0, Angle.ToRadians(90));
-        var line = new Line(0, 0, 10, 0);
-        var entities = new List<Entity> { arc, line };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Equal(2, entities.Count);
-    }
-
-    [Fact]
-    public void RemoveDuplicateArcs_MultipleArcsMatchOneCircle_RemovesAll()
-    {
-        var layer = new Layer("0");
-        var circle = new Circle(10, 10, 5) { Layer = layer };
-        var arc1 = new Arc(10, 10, 5, 0, Angle.ToRadians(90)) { Layer = layer };
-        var arc2 = new Arc(10, 10, 5, Angle.ToRadians(90), Angle.ToRadians(180)) { Layer = layer };
-        var entities = new List<Entity> { circle, arc1, arc2 };
-
-        CadImporter.RemoveDuplicateArcs(entities);
-
-        Assert.Single(entities);
-        Assert.Contains(circle, entities);
-    }
-}

OpenNest.Tests/Math/FractionTests.cs

@@ -1,46 +0,0 @@
-using OpenNest.Math;
-using Xunit;
-
-namespace OpenNest.Tests.Math;
-
-public class FractionTests
-{
-    [Theory]
-    [InlineData("3/8", 0.375)]
-    [InlineData("1 3/4", 1.75)]
-    [InlineData("1-3/4", 1.75)]
-    [InlineData("1/2", 0.5)]
-    public void Parse_ValidFraction_ReturnsDouble(string input, double expected)
-    {
-        var result = Fraction.Parse(input);
-
-        Assert.Equal(expected, result, 8);
-    }
-
-    [Theory]
-    [InlineData("3/8", true)]
-    [InlineData("abc", false)]
-    [InlineData("1 3/4", true)]
-    public void IsValid_ReturnsExpected(string input, bool expected)
-    {
-        Assert.Equal(expected, Fraction.IsValid(input));
-    }
-
-    [Fact]
-    public void TryParse_InvalidInput_ReturnsFalse()
-    {
-        var result = Fraction.TryParse("abc", out var value);
-
-        Assert.False(result);
-        Assert.Equal(0, value);
-    }
-
-    [Fact]
-    public void ReplaceFractionsWithDecimals_ReplacesFractionInString()
-    {
-        var result = Fraction.ReplaceFractionsWithDecimals("length is 1 3/4 inches");
-
-        Assert.Contains("1.75", result);
-        Assert.DoesNotContain("3/4", result);
-    }
-}

OpenNest.Training/Program.cs

@@ -89,10 +89,8 @@ int RunDataCollection(string dir, string dbPath, string saveDir, double s, strin
         new Size(48, 24), new Size(120, 10)
     };
 
-    var dxfFiles = Directory.GetFiles(dir, "*.dxf", SearchOption.AllDirectories)
-        .Concat(Directory.GetFiles(dir, "*.dwg", SearchOption.AllDirectories))
-        .ToArray();
-    Console.WriteLine($"Found {dxfFiles.Length} CAD files");
+    var dxfFiles = Directory.GetFiles(dir, "*.dxf", SearchOption.AllDirectories);
+    Console.WriteLine($"Found {dxfFiles.Length} DXF files");
     var resolvedDb = dbPath.EndsWith(".db", StringComparison.OrdinalIgnoreCase) ? dbPath : dbPath + ".db";
     Console.WriteLine($"Database: {Path.GetFullPath(resolvedDb)}");
     Console.WriteLine($"Sheet sizes: {sheetSuite.Length} configurations");

OpenNest/ArchUnits.cs

@@ -1,4 +1,4 @@
-using OpenNest.Math;
+using OpenNest.IO.Bom;
 using System;
 using System.Drawing;
 using System.Text;

OpenNest/Controls/CadText.cs

@@ -1,16 +0,0 @@
-using System.Drawing;
-using OpenNest.Geometry;
-
-namespace OpenNest.Controls
-{
-    public class CadText
-    {
-        public Vector Position { get; set; }
-        public string Value { get; set; }
-        public double Height { get; set; }
-        public double Rotation { get; set; }
-        public string LayerName { get; set; }
-        public StringAlignment HAlign { get; set; }
-        public StringAlignment VAlign { get; set; }
-    }
-}

OpenNest/Controls/EntityView.cs

@@ -29,14 +29,12 @@ namespace OpenNest.Controls
         public List<Entity> SimplifierToleranceRight { get; set; }
         public List<Entity> OriginalEntities { get; set; }
         public bool ShowEntityLabels { get; set; }
-        public List<CadText> Texts { get; set; } = new List<CadText>();
 
         private readonly Pen gridPen = new Pen(Color.FromArgb(70, 70, 70));
         private readonly Dictionary<int, Pen> penCache = new Dictionary<int, Pen>();
         private readonly Font labelFont = new Font("Segoe UI", 7f);
         private readonly SolidBrush labelBrush = new SolidBrush(Color.FromArgb(220, 255, 255, 200));
         private readonly SolidBrush labelBackBrush = new SolidBrush(Color.FromArgb(33, 40, 48));
-        private readonly SolidBrush textBrush = new SolidBrush(Color.FromArgb(180, 200, 200, 200));
 
         public event EventHandler<Line> LinePicked;
         public event EventHandler PickCancelled;
@@ -118,8 +116,6 @@ namespace OpenNest.Controls
                 DrawEntity(e.Graphics, entity, pen);
             }
 
-            DrawTexts(e.Graphics);
-
             if (ShowEntityLabels)
                 DrawEntityLabels(e.Graphics);
 
@@ -412,7 +408,6 @@ namespace OpenNest.Controls
                 labelFont.Dispose();
                 labelBrush.Dispose();
                 labelBackBrush.Dispose();
-                textBrush.Dispose();
             }
             base.Dispose(disposing);
         }
@@ -479,34 +474,6 @@ namespace OpenNest.Controls
                 diameter);
         }
 
-        private void DrawTexts(Graphics g)
-        {
-            if (Texts == null || Texts.Count == 0)
-                return;
-
-            using var sf = new StringFormat();
-
-            foreach (var text in Texts)
-            {
-                var pos = PointWorldToGraph(text.Position);
-                var fontSize = LengthWorldToGui(text.Height);
-                if (fontSize < 2f) continue;
-
-                var state = g.Save();
-                g.TranslateTransform(pos.X, pos.Y);
-
-                if (text.Rotation != 0)
-                    g.RotateTransform((float)OpenNest.Math.Angle.ToDegrees(text.Rotation));
-
-                sf.Alignment = text.HAlign;
-                sf.LineAlignment = text.VAlign;
-
-                using var font = new Font("Segoe UI", fontSize, GraphicsUnit.Pixel);
-                g.DrawString(text.Value, font, textBrush, 0, 0, sf);
-                g.Restore(state);
-            }
-        }
-
         private void DrawPoint(Graphics g, Vector pt, Pen pen)
         {
             var pt1 = PointWorldToGraph(pt);

OpenNest/Controls/FileListControl.cs

@@ -22,7 +22,6 @@ namespace OpenNest.Controls
         public HashSet<Guid> SuppressedEntityIds { get; set; }
         public Box Bounds { get; set; }
         public int EntityCount { get; set; }
-        public List<CadText> Texts { get; set; } = new();
     }
 
     public class FileListControl : Control

OpenNest/Forms/BomImportForm.cs

@@ -165,8 +165,7 @@ namespace OpenNest.Forms
                 else
                 {
                     var lookupName = item.FileName;
-                    if (lookupName.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase)
-                        || lookupName.EndsWith(".dwg", StringComparison.OrdinalIgnoreCase))
+                    if (lookupName.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase))
                         lookupName = Path.GetFileNameWithoutExtension(lookupName);
 
                     if (matchedPaths.TryGetValue(lookupName, out var dxfPath))

OpenNest/Forms/CadConverterForm.cs

@@ -92,8 +92,7 @@ namespace OpenNest.Forms
                     Customer = string.Empty,
                     Bends = result.Bends,
                     Bounds = result.Bounds,
-                    EntityCount = result.Entities.Count,
-                    Texts = ExtractTexts(result.Document),
+                    EntityCount = result.Entities.Count
                 };
 
                 if (InvokeRequired)
@@ -153,7 +152,6 @@ namespace OpenNest.Forms
             entityView1.Entities.Clear();
             entityView1.Entities.AddRange(item.Entities);
             entityView1.Bends = item.Bends ?? new List<Bend>();
-            entityView1.Texts = item.Texts ?? new List<CadText>();
 
             item.Entities.ForEach(e => e.IsVisible = true);
             if (item.Entities.Any(e => e.Layer != null))
@@ -475,8 +473,7 @@ namespace OpenNest.Forms
             {
                 var files = (string[])e.Data.GetData(DataFormats.FileDrop);
                 var dxfFiles = files.Where(f =>
-                    f.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase) ||
-                    f.EndsWith(".dwg", StringComparison.OrdinalIgnoreCase)).ToArray();
+                    f.EndsWith(".dxf", StringComparison.OrdinalIgnoreCase)).ToArray();
                 if (dxfFiles.Length > 0)
                     AddFiles(dxfFiles);
             }
@@ -806,102 +803,6 @@ namespace OpenNest.Forms
 
         #endregion
 
-        private static List<CadText> ExtractTexts(ACadSharp.CadDocument doc)
-        {
-            var texts = new List<CadText>();
-            if (doc == null) return texts;
-
-            foreach (var entity in doc.Entities)
-            {
-                switch (entity)
-                {
-                    case ACadSharp.Entities.MText mtext:
-                        var (mh, mv) = MapAttachmentPoint(mtext.AttachmentPoint);
-                        texts.Add(new CadText
-                        {
-                            Position = new Vector(mtext.InsertPoint.X, mtext.InsertPoint.Y),
-                            Value = ReplaceControlCodes(StripMTextFormatting(mtext.Value)),
-                            Height = mtext.Height,
-                            Rotation = mtext.Rotation,
-                            LayerName = mtext.Layer?.Name,
-                            HAlign = mh,
-                            VAlign = mv,
-                        });
-                        break;
-
-                    case ACadSharp.Entities.TextEntity text:
-                        var useAlignment = text.HorizontalAlignment != 0
-                            || text.VerticalAlignment != 0;
-                        var pt = useAlignment ? text.AlignmentPoint : text.InsertPoint;
-                        var ha = text.HorizontalAlignment switch
-                        {
-                            ACadSharp.Entities.TextHorizontalAlignment.Center => System.Drawing.StringAlignment.Center,
-                            ACadSharp.Entities.TextHorizontalAlignment.Right => System.Drawing.StringAlignment.Far,
-                            _ => System.Drawing.StringAlignment.Near,
-                        };
-                        texts.Add(new CadText
-                        {
-                            Position = new Vector(pt.X, pt.Y),
-                            Value = ReplaceControlCodes(text.Value),
-                            Height = text.Height,
-                            Rotation = text.Rotation,
-                            LayerName = text.Layer?.Name,
-                            HAlign = ha,
-                        });
-                        break;
-                }
-            }
-
-            return texts;
-        }
-
-        private static (System.Drawing.StringAlignment h, System.Drawing.StringAlignment v) MapAttachmentPoint(
-            ACadSharp.Entities.AttachmentPointType apt)
-        {
-            var h = apt switch
-            {
-                ACadSharp.Entities.AttachmentPointType.TopCenter
-                    or ACadSharp.Entities.AttachmentPointType.MiddleCenter
-                    or ACadSharp.Entities.AttachmentPointType.BottomCenter => System.Drawing.StringAlignment.Center,
-                ACadSharp.Entities.AttachmentPointType.TopRight
-                    or ACadSharp.Entities.AttachmentPointType.MiddleRight
-                    or ACadSharp.Entities.AttachmentPointType.BottomRight => System.Drawing.StringAlignment.Far,
-                _ => System.Drawing.StringAlignment.Near,
-            };
-            var v = apt switch
-            {
-                ACadSharp.Entities.AttachmentPointType.MiddleLeft
-                    or ACadSharp.Entities.AttachmentPointType.MiddleCenter
-                    or ACadSharp.Entities.AttachmentPointType.MiddleRight => System.Drawing.StringAlignment.Center,
-                ACadSharp.Entities.AttachmentPointType.BottomLeft
-                    or ACadSharp.Entities.AttachmentPointType.BottomCenter
-                    or ACadSharp.Entities.AttachmentPointType.BottomRight => System.Drawing.StringAlignment.Far,
-                _ => System.Drawing.StringAlignment.Near,
-            };
-            return (h, v);
-        }
-
-        private static string StripMTextFormatting(string text)
-        {
-            if (string.IsNullOrEmpty(text)) return text;
-            var result = System.Text.RegularExpressions.Regex.Replace(text, @"\\[A-Za-z][^;]*;", "");
-            result = result.Replace("{", "").Replace("}", "");
-            return result.Trim();
-        }
-
-        private static string ReplaceControlCodes(string text)
-        {
-            if (string.IsNullOrEmpty(text)) return text;
-            return text
-                .Replace("%%p", "±")
-                .Replace("%%P", "±")
-                .Replace("%%d", "°")
-                .Replace("%%D", "°")
-                .Replace("%%c", "⌀")
-                .Replace("%%C", "⌀")
-                .Replace("%%%", "%");
-        }
-
         private void filterPanel_Paint(object sender, PaintEventArgs e)
         {
 

OpenNest/Forms/EditNestForm.cs

@@ -329,7 +329,7 @@ namespace OpenNest.Forms
         {
             var dlg = new OpenFileDialog();
             dlg.Multiselect = true;
-            dlg.Filter = "CAD Files (*.dxf;*.dwg)|*.dxf;*.dwg|DXF Files (*.dxf)|*.dxf|DWG Files (*.dwg)|*.dwg";
+            dlg.Filter = "DXF Files (*.dxf) | *.dxf";
 
             if (dlg.ShowDialog() != DialogResult.OK)
                 return;
@@ -346,6 +346,7 @@ namespace OpenNest.Forms
             drawings.ForEach(d => Nest.Drawings.Add(d));
 
             UpdateDrawingList();
+            tabControl1.SelectedIndex = 1;
         }
 
         public bool Export()

OpenNest/GraphicsHelper.cs

@@ -138,20 +138,9 @@ namespace OpenNest
                         break;
 
                     case CodeType.RapidMove:
-                        {
-                            var rapid = (RapidMove)code;
-                            var endpt = rapid.EndPoint;
-                            if (mode == Mode.Incremental)
-                                endpt += curpos;
-                            var dx = endpt.X - curpos.X;
-                            var dy = endpt.Y - curpos.Y;
-                            if (dx * dx + dy * dy > 0.001 * 0.001)
-                            {
                         cutPath.StartFigure();
                         leadPath.StartFigure();
-                            }
-                            curpos = endpt;
-                        }
+                        AddLine(cutPath, (RapidMove)code, mode, ref curpos);
                         break;
 
                     case CodeType.SubProgramCall:
@@ -311,17 +300,8 @@ namespace OpenNest
                         break;
 
                     case CodeType.RapidMove:
-                        {
-                            var rapid = (RapidMove)code;
-                            var endpt = rapid.EndPoint;
-                            if (mode == Mode.Incremental)
-                                endpt += curpos;
-                            var dx = endpt.X - curpos.X;
-                            var dy = endpt.Y - curpos.Y;
-                            if (dx * dx + dy * dy > 0.001 * 0.001)
                         Flush();
-                            curpos = endpt;
-                        }
+                        AddLine(path, (RapidMove)code, mode, ref curpos);
                         break;
 
                     case CodeType.SubProgramCall: