feat: serialize/deserialize cut-off definitions in nest file format

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

OpenNest.IO/NestFormat.cs

@@ -62,6 +62,7 @@ namespace OpenNest.IO
             public MaterialDto Material { get; init; } = new();
             public SpacingDto EdgeSpacing { get; init; } = new();
             public List<PartDto> Parts { get; init; } = new();
+            public List<CutOffDto> CutOffs { get; init; } = new();
         }
 
         public record PartDto
@@ -72,6 +73,15 @@ namespace OpenNest.IO
             public double Rotation { get; init; }
         }
 
+        public record CutOffDto
+        {
+            public double X { get; init; }
+            public double Y { get; init; }
+            public string Axis { get; init; } = "vertical";
+            public double? StartLimit { get; init; }
+            public double? EndLimit { get; init; }
+        }
+
         public record SizeDto
         {
             public double Width { get; init; }

OpenNest.IO/NestReader.cs

@@ -197,6 +197,25 @@ namespace OpenNest.IO
                     plate.Parts.Add(part);
                 }
 
+                // Cut-offs
+                if (p.CutOffs != null)
+                {
+                    foreach (var cutoffDto in p.CutOffs)
+                    {
+                        var axis = cutoffDto.Axis?.ToLowerInvariant() == "horizontal"
+                            ? CutOffAxis.Horizontal
+                            : CutOffAxis.Vertical;
+                        var cutoff = new CutOff(new Vector(cutoffDto.X, cutoffDto.Y), axis)
+                        {
+                            StartLimit = cutoffDto.StartLimit,
+                            EndLimit = cutoffDto.EndLimit
+                        };
+                        plate.CutOffs.Add(cutoff);
+                    }
+
+                    plate.RegenerateCutOffs(new CutOffSettings());
+                }
+
                 nest.Plates.Add(plate);
             }
 

OpenNest.IO/NestWriter.cs

@@ -152,7 +152,7 @@ namespace OpenNest.IO
             {
                 var plate = nest.Plates[i];
                 var parts = new List<PartDto>();
-                foreach (var part in plate.Parts)
+                foreach (var part in plate.Parts.Where(p => !p.BaseDrawing.IsCutOff))
                 {
                     var match = drawingDict.Where(dwg => dwg.Value == part.BaseDrawing).FirstOrDefault();
                     parts.Add(new PartDto
@@ -164,6 +164,19 @@ namespace OpenNest.IO
                     });
                 }
 
+                var cutoffs = new List<CutOffDto>();
+                foreach (var cutoff in plate.CutOffs)
+                {
+                    cutoffs.Add(new CutOffDto
+                    {
+                        X = cutoff.Position.X,
+                        Y = cutoff.Position.Y,
+                        Axis = cutoff.Axis == CutOffAxis.Vertical ? "vertical" : "horizontal",
+                        StartLimit = cutoff.StartLimit,
+                        EndLimit = cutoff.EndLimit
+                    });
+                }
+
                 list.Add(new PlateDto
                 {
                     Id = i + 1,
@@ -185,7 +198,8 @@ namespace OpenNest.IO
                         Right = plate.EdgeSpacing.Right,
                         Bottom = plate.EdgeSpacing.Bottom
                     },
-                    Parts = parts
+                    Parts = parts,
+                    CutOffs = cutoffs
                 });
             }
             return list;