fix: detect winding direction for correct part spacing offset

PolygonHelper.ExtractPerimeterPolygon always used OffsetSide.Right
assuming CCW winding, but DXF imports can produce CW winding. This
caused the spacing polygon to shrink inward instead of expanding
outward, making parts overlap during nesting.

Now detects winding direction via polygon signed area and selects
the correct OffsetSide accordingly.

Also adds save_nest MCP tool and a BOM-to-nest builder utility
(tools/NestBuilder) for batch-creating nest files from Excel BOMs.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-03-23 21:57:23 -04:00
parent aeeb2e4074
commit 072915abf2
5 changed files with 299 additions and 2 deletions

View File

@@ -23,9 +23,17 @@ namespace OpenNest.Engine.BestFit
return new PolygonExtractionResult(null, Vector.Zero);
// Inflate by half-spacing if spacing is non-zero.
// OffsetSide.Right = outward for CCW perimeters (standard for outer contours).
// Detect winding direction to choose the correct outward offset side.
var outwardSide = OffsetSide.Right;
if (halfSpacing > 0)
{
var testPoly = perimeter.ToPolygon();
if (testPoly.Vertices.Count >= 3 && testPoly.RotationDirection() == RotationType.CW)
outwardSide = OffsetSide.Left;
}
var inflated = halfSpacing > 0
? (perimeter.OffsetEntity(halfSpacing, OffsetSide.Right) as Shape ?? perimeter)
? (perimeter.OffsetEntity(halfSpacing, outwardSide) as Shape ?? perimeter)
: perimeter;
// Convert to polygon with circumscribed arcs for tight nesting.

View File

@@ -57,6 +57,35 @@ namespace OpenNest.Mcp.Tools
return sb.ToString();
}
[McpServerTool(Name = "save_nest")]
[Description("Save the current session (all drawings and plates) to a .nest file.")]
public string SaveNest(
[Description("Absolute path for the output .nest file")] string path,
[Description("Name for the nest (optional)")] string name = null)
{
var nest = new Nest();
nest.Name = name ?? Path.GetFileNameWithoutExtension(path);
foreach (var drawing in _session.AllDrawings())
nest.Drawings.Add(drawing);
foreach (var plate in _session.AllPlates())
nest.Plates.Add(plate);
if (nest.Drawings.Count == 0)
return "Error: no drawings in session to save";
var dir = Path.GetDirectoryName(path);
if (!string.IsNullOrEmpty(dir) && !Directory.Exists(dir))
Directory.CreateDirectory(dir);
var writer = new NestWriter(nest);
if (!writer.Write(path))
return "Error: failed to write nest file";
return $"Saved nest to {path}\n Drawings: {nest.Drawings.Count}\n Plates: {nest.Plates.Count}";
}
[McpServerTool(Name = "import_dxf")]
[Description("Import a DXF file as a new drawing. Returns drawing name and bounding box.")]
public string ImportDxf(

View File

@@ -36,6 +36,47 @@ public class PolygonHelperTests
$"With-spacing width: {withSpacing.Polygon.BoundingBox.Width:F3}");
}
[Fact]
public void ExtractPerimeterPolygon_InflatedPolygonIsLarger_ForCWWinding()
{
// CW winding (standard CNC convention): (0,0)→(0,10)→(10,10)→(10,0)→(0,0)
var drawing = TestHelpers.MakeSquareDrawing(10);
var noSpacing = PolygonHelper.ExtractPerimeterPolygon(drawing, 0);
var withSpacing = PolygonHelper.ExtractPerimeterPolygon(drawing, 1);
noSpacing.Polygon.UpdateBounds();
withSpacing.Polygon.UpdateBounds();
Assert.True(withSpacing.Polygon.BoundingBox.Width > noSpacing.Polygon.BoundingBox.Width,
$"Inflated width {withSpacing.Polygon.BoundingBox.Width:F3} should be > original {noSpacing.Polygon.BoundingBox.Width:F3}");
Assert.True(withSpacing.Polygon.BoundingBox.Length > noSpacing.Polygon.BoundingBox.Length,
$"Inflated length {withSpacing.Polygon.BoundingBox.Length:F3} should be > original {noSpacing.Polygon.BoundingBox.Length:F3}");
}
[Fact]
public void ExtractPerimeterPolygon_InflatedPolygonIsLarger_ForCCWWinding()
{
// CCW winding: (0,0)→(10,0)→(10,10)→(0,10)→(0,0)
var pgm = new CNC.Program();
pgm.Codes.Add(new CNC.RapidMove(new Vector(0, 0)));
pgm.Codes.Add(new CNC.LinearMove(new Vector(10, 0)));
pgm.Codes.Add(new CNC.LinearMove(new Vector(10, 10)));
pgm.Codes.Add(new CNC.LinearMove(new Vector(0, 10)));
pgm.Codes.Add(new CNC.LinearMove(new Vector(0, 0)));
var drawing = new Drawing("ccw-square", pgm);
var noSpacing = PolygonHelper.ExtractPerimeterPolygon(drawing, 0);
var withSpacing = PolygonHelper.ExtractPerimeterPolygon(drawing, 1);
noSpacing.Polygon.UpdateBounds();
withSpacing.Polygon.UpdateBounds();
Assert.True(withSpacing.Polygon.BoundingBox.Width > noSpacing.Polygon.BoundingBox.Width,
$"Inflated width {withSpacing.Polygon.BoundingBox.Width:F3} should be > original {noSpacing.Polygon.BoundingBox.Width:F3}");
Assert.True(withSpacing.Polygon.BoundingBox.Length > noSpacing.Polygon.BoundingBox.Length,
$"Inflated length {withSpacing.Polygon.BoundingBox.Length:F3} should be > original {noSpacing.Polygon.BoundingBox.Length:F3}");
}
[Fact]
public void ExtractPerimeterPolygon_ReturnsNull_ForEmptyDrawing()
{

View File

@@ -0,0 +1,10 @@
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net8.0-windows</TargetFramework>
</PropertyGroup>
<ItemGroup>
<ProjectReference Include="..\..\OpenNest.Core\OpenNest.Core.csproj" />
<ProjectReference Include="..\..\OpenNest.IO\OpenNest.IO.csproj" />
</ItemGroup>
</Project>

View File

@@ -0,0 +1,209 @@
using System;
using System.Drawing;
using System.IO;
using System.Linq;
using OpenNest;
using OpenNest.Converters;
using OpenNest.Geometry;
using Size = OpenNest.Geometry.Size;
using OpenNest.IO;
var partColors = new Color[]
{
Color.FromArgb(205, 92, 92), // Indian Red
Color.FromArgb(148, 103, 189), // Medium Purple
Color.FromArgb(75, 180, 175), // Teal
Color.FromArgb(210, 190, 75), // Goldenrod
Color.FromArgb(190, 85, 175), // Orchid
Color.FromArgb(185, 115, 85), // Sienna
Color.FromArgb(120, 100, 190), // Slate Blue
Color.FromArgb(200, 100, 140), // Rose
Color.FromArgb(80, 175, 155), // Sea Green
Color.FromArgb(195, 160, 85), // Dark Khaki
Color.FromArgb(175, 95, 160), // Plum
Color.FromArgb(215, 130, 130), // Light Coral
};
var templateDir = @"C:\Users\AJ\Desktop\Projects\OpenNest\docs\Templates";
var outputDir = @"C:\Users\AJ\Desktop\Projects\OpenNest\docs\Templates\Nests";
Directory.CreateDirectory(outputDir);
// BOM: (fileName, qty, thickness, material)
var bom = new (string File, int Qty, double Thickness, string Material)[]
{
("PT01", 2, 0.250, "304SS"),
("PT02", 5, 0.625, "304SS"),
("PT03", 4, 0.250, "304SS"),
("PT04", 4, 0.250, "304SS"),
("PT05", 1, 0.250, "304SS"),
("PT06", 21, 0.375, "304SS"),
("PT07", 2, 0.250, "304SS"),
("PT08", 22, 0.250, "304SS"),
("PT11", 2, 0.1875, "304SS"),
("PT12", 2, 0.1875, "304SS"),
("PT13", 6, 0.1875, "304SS"),
("PT15", 6, 0.1875, "304SS"),
("PT16", 6, 0.1875, "304SS"),
("PT18", 3, 0.250, "304SS"),
("PT19", 3, 0.1875, "304SS"),
("PT20", 2, 0.1196, "304SS"),
("PT21", 6, 0.1196, "304SS"),
("PT22", 2, 0.1196, "304SS"),
("PT23", 1, 0.0598, "304SS"),
("PT24", 1, 0.0598, "304SS"),
("PT26", 4, 0.250, "304SS"),
("PT27", 2, 0.250, "304SS"),
("PT28", 4, 0.250, "304SS"),
("PT29", 6, 0.250, "304SS"),
("PT33", 2, 0.250, "304SS"),
("PT34", 4, 0.250, "304SS"),
("PT35", 3, 0.1875, "304SS"),
("PT36", 4, 0.1875, "304SS"),
("PT37", 4, 0.1875, "304SS"),
("PT38", 4, 0.1875, "304SS"),
("PT39", 2, 0.0598, "304SS"),
("PT40", 4, 0.0598, "304SS"),
("PT41", 1, 0.1875, "304SS"),
("PT43", 1, 0.0598, "304SS"),
("PT44", 1, 0.0598, "304SS"),
("PT45", 1, 0.250, "304SS"),
("PT46", 2, 0.250, "304SS"),
("PT47", 4, 0.250, "304SS"),
("PT48", 1, 0.250, "304SS"),
("PT49", 1, 0.750, "PCS"),
("PT50", 2, 0.375, "PCS"),
("PT51", 1, 0.250, "304SS"),
("PT52", 1, 0.1875, "304SS"),
("PT53", 1, 0.1875, "304SS"),
("PT54", 2, 0.250, "304SS"),
("PT55", 1, 0.1196, "304SS"),
("PT56", 1, 0.1196, "304SS"),
("PT57", 1, 0.0598, "304SS"),
("PT58", 1, 0.0598, "304SS"),
};
// Group by material + thickness
var groups = bom.GroupBy(b => (b.Material, b.Thickness)).OrderBy(g => g.Key.Material).ThenBy(g => g.Key.Thickness);
foreach (var group in groups)
{
var material = group.Key.Material;
var thickness = group.Key.Thickness;
var thicknessLabel = thickness switch
{
0.0598 => "16GA",
0.1196 => "11GA",
0.1875 => "3-16",
0.250 => "1-4",
0.375 => "3-8",
0.625 => "5-8",
0.750 => "3-4",
_ => thickness.ToString("F4")
};
var nestName = $"4526 A14 - {material} {thicknessLabel}";
Console.WriteLine($"\n=== {nestName} ===");
var nest = new Nest();
nest.Name = nestName;
nest.PlateDefaults.Thickness = thickness;
nest.PlateDefaults.Material = new Material { Name = material };
nest.PlateDefaults.PartSpacing = 0.125;
nest.PlateDefaults.EdgeSpacing = new Spacing(0.25, 0.25, 0.25, 0.25);
// Import DXFs for this group
var importer = new DxfImporter();
var colorIndex = 0;
double maxMinDim = 0;
double maxMaxDim = 0;
foreach (var item in group)
{
var dxfPath = Path.Combine(templateDir, $"4526 A14 {item.File}.dxf");
if (!File.Exists(dxfPath))
{
Console.WriteLine($" WARNING: {dxfPath} not found, skipping");
continue;
}
if (!importer.GetGeometry(dxfPath, out var geometry) || geometry.Count == 0)
{
Console.WriteLine($" WARNING: no geometry in {item.File}, skipping");
continue;
}
var pgm = ConvertGeometry.ToProgram(geometry);
if (pgm == null)
{
Console.WriteLine($" WARNING: failed to convert {item.File}, skipping");
continue;
}
var drawing = new Drawing(item.File, pgm);
drawing.Quantity.Required = item.Qty;
drawing.Material = new Material { Name = material };
drawing.Color = partColors[colorIndex % partColors.Length];
colorIndex++;
nest.Drawings.Add(drawing);
var bbox = pgm.BoundingBox();
var minDim = System.Math.Min(bbox.Width, bbox.Length);
var maxDim = System.Math.Max(bbox.Width, bbox.Length);
maxMinDim = System.Math.Max(maxMinDim, minDim);
maxMaxDim = System.Math.Max(maxMaxDim, maxDim);
Console.WriteLine($" {item.File}: {bbox.Width:F2} x {bbox.Length:F2}, qty={item.Qty}");
}
// Choose plate size based on largest part dimensions
// Size(width, length) — width is the short side, length is the long side
// Standard sizes: 48x96, 48x120, 60x120, 60x144, 72x144, 96x120
double plateW, plateL;
if (maxMinDim <= 47.5 && maxMaxDim <= 95.5)
{
plateW = 48; plateL = 96;
}
else if (maxMinDim <= 47.5 && maxMaxDim <= 119.5)
{
plateW = 48; plateL = 120;
}
else if (maxMinDim <= 59.5 && maxMaxDim <= 119.5)
{
plateW = 60; plateL = 120;
}
else if (maxMinDim <= 59.5 && maxMaxDim <= 143.5)
{
plateW = 60; plateL = 144;
}
else if (maxMinDim <= 71.5 && maxMaxDim <= 143.5)
{
plateW = 72; plateL = 144;
}
else if (maxMinDim <= 95.5 && maxMaxDim <= 119.5)
{
plateW = 96; plateL = 120;
}
else
{
// Fallback: round up to nearest 12"
plateW = System.Math.Ceiling((maxMinDim + 1) / 12.0) * 12;
plateL = System.Math.Ceiling((maxMaxDim + 1) / 12.0) * 12;
}
// Create one empty plate via PlateDefaults so it inherits settings
nest.PlateDefaults.Size = new Size(plateW, plateL);
var plate = nest.CreatePlate();
plate.Quantity = 1;
Console.WriteLine($" Plate size: {plateW} x {plateL} (W x L)");
Console.WriteLine($" Drawings: {nest.Drawings.Count}");
var outputPath = Path.Combine(outputDir, $"{nestName}.nest");
var writer = new NestWriter(nest);
if (writer.Write(outputPath))
Console.WriteLine($" Saved: {outputPath}");
else
Console.WriteLine($" ERROR: failed to save {outputPath}");
}
Console.WriteLine("\nDone!");