OpenNest/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

OpenNest is a Windows desktop application for CNC nesting — arranging 2D parts on material plates to minimize waste. It imports DXF drawings, places parts onto plates using NFP-based (No Fit Polygon) and rectangle-packing algorithms, and can export nest layouts as DXF or post-process them to G-code for CNC cutting machines.

## Build

This is a .NET 8 solution using SDK-style `.csproj` files targeting `net8.0-windows`. Build with:

```bash
dotnet build OpenNest.sln
```

NuGet dependencies: `ACadSharp` 3.1.32 (DXF/DWG import/export, in OpenNest.IO), `System.Drawing.Common` 8.0.10, `ModelContextProtocol` + `Microsoft.Extensions.Hosting` (in OpenNest.Mcp), `Microsoft.ML.OnnxRuntime` (in OpenNest.Engine for ML angle prediction), `Microsoft.EntityFrameworkCore.Sqlite` (in OpenNest.Training).

## Architecture

Eight projects form a layered architecture:

### OpenNest.Core (class library)
Domain model, geometry, and CNC primitives organized into namespaces:

- **Root** (`namespace OpenNest`): Domain model — `Nest` → `Plate[]` → `Part[]` → `Drawing` → `Program`. A `Nest` is the top-level container. Each `Plate` has a size, material, quadrant, spacing, and contains placed `Part` instances. Each `Part` references a `Drawing` (the template) and has its own location/rotation. A `Drawing` wraps a CNC `Program`. Also contains utilities: `PartGeometry`, `Align`, `Sequence`, `Timing`.
- **CNC** (`CNC/`, `namespace OpenNest.CNC`): `Program` holds a list of `ICode` instructions (G-code-like: `RapidMove`, `LinearMove`, `ArcMove`, `SubProgramCall`). Programs support absolute/incremental mode conversion, rotation, offset, bounding box calculation, and cloning.
- **Geometry** (`Geometry/`, `namespace OpenNest.Geometry`): Spatial primitives (`Vector`, `Box`, `Size`, `Spacing`, `BoundingBox`, `IBoundable`) and higher-level shapes (`Line`, `Arc`, `Circle`, `Polygon`, `Shape`) used for intersection detection, area calculation, and DXF conversion. Also contains `Intersect` (intersection algorithms), `ShapeBuilder` (entity chaining), `GeometryOptimizer` (line/arc merging), `SpatialQuery` (directional distance, ray casting, box queries), `ShapeProfile` (perimeter/area analysis), `NoFitPolygon`, `InnerFitPolygon`, `ConvexHull`, `ConvexDecomposition`, and `RotatingCalipers`.
- **Converters** (`Converters/`, `namespace OpenNest.Converters`): Bridges between CNC and Geometry — `ConvertProgram` (CNC→Geometry), `ConvertGeometry` (Geometry→CNC), `ConvertMode` (absolute↔incremental).
- **Math** (`Math/`, `namespace OpenNest.Math`): `Angle` (radian/degree conversion), `Tolerance` (floating-point comparison), `Trigonometry`, `Generic` (swap utility), `EvenOdd`, `Rounding` (factor-based rounding). Note: `OpenNest.Math` shadows `System.Math` — use `System.Math` fully qualified where both are needed.
- **CNC/CuttingStrategy** (`CNC/CuttingStrategy/`, `namespace OpenNest.CNC`): `ContourCuttingStrategy` orchestrates cut ordering, lead-ins/lead-outs, and tabs. Includes `LeadIn`/`LeadOut` hierarchies (line, arc, clean-hole variants), `Tab` hierarchy (normal, machine, breaker), and `CuttingParameters`/`AssignmentParameters`/`SequenceParameters` configuration.
- **Collections** (`Collections/`, `namespace OpenNest.Collections`): `ObservableList<T>`, `DrawingCollection`.
- **Quadrant system**: Plates use quadrants 1-4 (like Cartesian quadrants) to determine coordinate origin placement. This affects bounding box calculation, rotation, and part positioning.

### OpenNest.Engine (class library, depends on Core)
Nesting algorithms with a pluggable engine architecture. `NestEngineBase` is the abstract base class; `DefaultNestEngine` (formerly `NestEngine`) provides the multi-phase fill strategy. `NestEngineRegistry` manages available engines (built-in + plugins from `Engines/` directory) and the globally active engine. `AutoNester` handles mixed-part NFP-based nesting with simulated annealing (not yet integrated into the registry).

- **Engine hierarchy**: `NestEngineBase` (abstract) → `DefaultNestEngine` (Linear, Pairs, RectBestFit, Remainder phases). Custom engines subclass `NestEngineBase` and register via `NestEngineRegistry.Register()` or as plugin DLLs in `Engines/`.
- **NestEngineRegistry**: Static registry — `Create(Plate)` factory, `ActiveEngineName` global selection, `LoadPlugins(directory)` for DLL discovery. All callsites use `NestEngineRegistry.Create(plate)` except `BruteForceRunner` which uses `new DefaultNestEngine(plate)` directly for training consistency.
- **Fill/** (`namespace OpenNest.Engine.Fill`): Fill algorithms — `FillLinear` (grid-based), `FillExtents` (extents-based pair tiling), `PairFiller` (interlocking pairs), `ShrinkFiller`, `RemnantFiller`/`RemnantFinder`, `Compactor` (post-fill gravity compaction), `FillScore` (lexicographic comparison: count > utilization > compactness), `Pattern`/`PatternTiler`, `PartBoundary`, `RotationAnalysis`, `AngleCandidateBuilder`, `BestCombination`, `AccumulatingProgress`.
- **Strategies/** (`namespace OpenNest.Engine.Strategies`): Pluggable fill strategy layer — `IFillStrategy` interface, `FillContext`, `FillStrategyRegistry` (auto-discovers strategies via reflection, supports plugin DLLs), `FillHelpers`. Built-in strategies: `LinearFillStrategy`, `PairsFillStrategy`, `RectBestFitStrategy`, `ExtentsFillStrategy`.
- **BestFit/** (`namespace OpenNest.Engine.BestFit`): NFP-based pair evaluation pipeline — `BestFitFinder` orchestrates angle sweeps, `PairEvaluator`/`IPairEvaluator` scores part pairs, `RotationSlideStrategy`/`ISlideComputer` computes slide distances. `BestFitCache` and `BestFitFilter` optimize repeated lookups.
- **RectanglePacking/** (`namespace OpenNest.RectanglePacking`): `FillBestFit` (single-item fill, tries horizontal and vertical orientations), `PackBottomLeft` (multi-item bin packing, sorts by area descending). Both operate on `Bin`/`Item` abstractions.
- **CirclePacking/** (`namespace OpenNest.CirclePacking`): Alternative packing for circular parts.
- **Nfp/** (`namespace OpenNest.Engine.Nfp`): NFP-based nesting (not yet integrated) — `AutoNester` (mixed-part nesting with simulated annealing), `BottomLeftFill` (BLF placement), `NfpCache` (computed NFP caching), `SimulatedAnnealing` (optimizer), `INestOptimizer`/`NestResult`.
- **ML/** (`namespace OpenNest.Engine.ML`): `AnglePredictor` (ONNX model for predicting good rotation angles), `FeatureExtractor` (part geometry features), `BruteForceRunner` (full angle sweep for training data).
- `NestItem`: Input to the engine — wraps a `Drawing` with quantity, priority, and rotation constraints.
- `NestProgress`: Progress reporting model with `NestPhase` enum for UI feedback.

### OpenNest.IO (class library, depends on Core)
File I/O and format conversion. Uses ACadSharp for DXF/DWG support.

- `DxfImporter`/`DxfExporter` — DXF file import/export via ACadSharp.
- `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.

### 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`).

### OpenNest.Gpu (class library, depends on Core + Engine)
GPU-accelerated pair evaluation for best-fit nesting. `GpuPairEvaluator` implements `IPairEvaluator`, `GpuSlideComputer` implements `ISlideComputer`, and `PartBitmap` handles rasterization. `GpuEvaluatorFactory` provides factory methods.

### OpenNest.Training (console app, depends on Core + Engine)
Training data collection for ML angle prediction. `TrainingDatabase` stores per-angle nesting results in SQLite via EF Core for offline model training.

### OpenNest.Mcp (console app, depends on Core + Engine + IO)
MCP server for Claude Code integration. Exposes nesting operations as MCP tools over stdio transport. Published to `~/.claude/mcp/OpenNest.Mcp/`.

- **Tools/InputTools**: `load_nest`, `import_dxf`, `create_drawing` (built-in shapes or G-code).
- **Tools/SetupTools**: `create_plate`, `clear_plate`.
- **Tools/NestingTools**: `fill_plate`, `fill_area`, `fill_remnants`, `pack_plate`.
- **Tools/InspectionTools**: `get_plate_info`, `get_parts`, `check_overlaps`.
- `NestSession` — in-memory state across tool calls (current Nest, standalone plates/drawings).

### OpenNest (WinForms WinExe, depends on Core + Engine + IO)
The UI application with MDI interface.

- **Forms/**: `MainForm` (MDI parent), `EditNestForm` (MDI child per nest), plus dialogs for plate editing, auto-nesting, DXF conversion, cut parameters, etc.
- **Controls/**: `PlateView` (2D plate renderer with zoom/pan, supports temporary preview parts), `DrawingListBox`, `DrawControl`, `QuadrantSelect`.
- **Actions/**: User interaction modes — `ActionSelect`, `ActionClone`, `ActionFillArea`, `ActionSelectArea`, `ActionZoomWindow`, `ActionSetSequence`.
- **Post-processing**: `IPostProcessor` plugin interface loaded from DLLs in a `Posts/` directory at runtime.

## File Format

Nest files (`.nest`, ZIP-based) use v2 JSON format:
- `info.json` — nest metadata and plate defaults
- `drawing-info.json` — drawing metadata (name, material, quantities, colors)
- `plate-info.json` — plate metadata (size, material, spacing)
- `program-NNN` — G-code text for each drawing's cut program
- `plate-NNN` — G-code text encoding part placements (G00 for position, G65 for sub-program call with rotation)

## Tool Preferences

Always use Roslyn Bridge MCP tools (`mcp__RoslynBridge__*`) as the primary method for exploring and analyzing this codebase. It is faster and more efficient than file-based searches. Use it for finding symbols, references, diagnostics, type hierarchies, and code navigation. Only fall back to Glob/Grep when Roslyn Bridge cannot fulfill the query.

## Code Style

- Always use `var` instead of explicit types (e.g., `var parts = new List<Part>();` not `List<Part> parts = new List<Part>();`).

## Documentation Maintenance

Always keep `README.md` and `CLAUDE.md` up to date when making changes that affect project structure, architecture, build instructions, dependencies, or key patterns. If you add a new project, change a namespace, modify the build process, or alter significant behavior, update both files as part of the same change.

## Key Patterns

- OpenNest.Core uses multiple namespaces: `OpenNest` (root domain), `OpenNest.CNC`, `OpenNest.Geometry`, `OpenNest.Converters`, `OpenNest.Math`, `OpenNest.Collections`.
- OpenNest.Engine uses sub-namespaces: `OpenNest.Engine.Fill` (fill algorithms), `OpenNest.Engine.Strategies` (pluggable strategy layer), `OpenNest.Engine.BestFit`, `OpenNest.Engine.Nfp` (NFP-based nesting, not yet integrated), `OpenNest.Engine.ML`, `OpenNest.Engine.RapidPlanning`, `OpenNest.Engine.Sequencing`.
- `ObservableList<T>` provides ItemAdded/ItemRemoved/ItemChanged events used for automatic quantity tracking between plates and drawings.
- Angles throughout the codebase are in **radians** (use `Angle.ToRadians()`/`Angle.ToDegrees()` for conversion).
- `Tolerance.Epsilon` is used for floating-point comparisons across geometry operations.
- Nesting uses async progress/cancellation: `IProgress<NestProgress>` and `CancellationToken` flow through the engine to the UI's `NestProgressForm`.
- `Compactor` performs post-fill gravity compaction — after filling, parts are pushed toward a plate edge using directional distance calculations to close gaps between irregular shapes.
- `FillScore` uses lexicographic comparison (count > utilization > compactness) to rank fill results consistently across all fill strategies.