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OpenNest
A Windows desktop application for CNC nesting — imports DXF drawings, arranges parts on material plates, and exports layouts as DXF or G-code for cutting.
Features
- Import / export — DXF & DWG parts (ACadSharp), Excel BOMs, bend-line detection, built-in parametric shapes; export DXF or post-processed G-code.
- Nesting — pluggable whole-job engines (Default, Strip, Vertical/Horizontal Remnant, StockLadder, plus DLL plugins), NFP-based interlocking pair evaluation, gravity compaction, rotation sweeps, multi-plate/multi-material jobs.
- Plate operations — manual sheet cut-offs, plate- or nest-wide automatic scrap cutoffs with a minimum tail-to-keep setting, oversized-part splitting (straight, weld-gap tabs, spike-groove), interactive editing, and spacing-aware pushes that can slide along or away from touching parts.
- Visual overlap check — highlight shared material on the active plate, rechecked automatically after edits, including containment and cutouts, with area shading, pair centroids, and hover details through View > Overlap Check. Usage and limitations.
- CNC output — configurable lead-ins/outs and tabs, contour editing, user-defined G-code variables (
$name→#200+machine variables), plugin post-processors (Cincinnati CL-707/800/900/940/CLX included). Pre-post verification checks overlaps, missing lead-ins, and rapid crossings, with explicit risk acknowledgment required to bypass warnings.
Requirements
- Windows 10+ for the desktop app; the console, API, and most test projects build on Linux/macOS too.
- .NET 8 SDK to build from source.
Windows release ZIPs are self-contained: extract the entire archive into a new folder and run OpenNest.exe; no separate .NET installation is needed. The Rectangles and Irregular nesting engines are built in; see nesting engines. Use the ZIP and SHA-256 checksum from GitHub Releases, not the source-code archives.
Build, Test, Run
git clone https://git.thecozycat.net/aj/OpenNest.git
cd OpenNest
dotnet build OpenNest.sln # full solution (Windows)
dotnet test OpenNest.Engine.Tests/OpenNest.Engine.Tests.csproj # cross-platform engine tests
dotnet test OpenNest.Tests/OpenNest.Tests.csproj # core/engine/IO/API tests
dotnet test OpenNest.FrontEnd.Tests/OpenNest.FrontEnd.Tests.csproj # console/MCP/API integration
dotnet run --project OpenNest/OpenNest.csproj # desktop app (Windows)
OpenNest.WinForms.Tests (desktop-assembly tests) runs on Windows only. Format changed files with dotnet format OpenNest.sln --include <path>.
Shared coding-agent guidance lives in AGENTS.md. CLAUDE.md imports it for Claude Code compatibility; make shared instruction changes in AGENTS.md, not in duplicate agent-specific copies.
Quick start
- File > New Nest
- Import DXFs via the CAD Converter (layer/color filtering, bend detection, G-code preview) or create built-in shapes
- Define plate size, material, quadrant, spacing
- Fill — the engine arranges parts
- Optionally add cut-off lines, apply Part Sequencing to order crossing cut-offs before their parts, then save
.nest, export DXF, or post-process to G-code
Review part spacing before cutting, especially for interlocking pairs. See pair-spacing checks and current limitations.
Command-Line Interface
dotnet run --project OpenNest.Console -- part.dxf --size 60x120 # fill one plate
dotnet run --project OpenNest.Console -- part1.dxf part2.dxf --size 60x120 --autonest
dotnet run --project OpenNest.Console -- project.zip # re-fill a nest file
Key options: --size WxL, --autonest (validated single-sheet whole-job nesting), --allow-invalid (explicit warning override), --engine <name> (jobs engine or fill strategy), --quantity, --spacing, --template <nest>, --output <path>, --check-overlaps, --post <name>, --no-save. Run without arguments for the full list.
Benchmarking Engines
OpenNest.Benchmark runs every registered INestingEngine against .nest files (or a JSON manifest of DXFs + quantities) and scores by salvage-credited sheet area, with a penalty per unplaced part.
dotnet run --project OpenNest.Benchmark -- ./benchmark-jobs \
--sheet-sizes 48x96,60x120,72x120 --engines Default,StockLadder --csv results.csv
Layouts are validated (bounds, spacing, quantity, rotation, stock match); invalid runs place nothing and pay the penalty. --parallel (default 3) speeds up scoring but inflates Time(ms) — use --parallel 1 when comparing speed. Pass --sheet-sizes for an unbiased run; otherwise only each file's original sizes are offered. --progress logs each solve's start, the engine's NestJobProgress (plate evaluations throttled to one line per 2 s, every plate commit) and its finish. Custom engines drop in as DLLs implementing INestingEngine (public parameterless constructor) in an Engines/ folder next to the benchmark. Built-in engines and how to change them: nesting engines.
Project Structure
| Project | Purpose |
|---|---|
| OpenNest | WinForms desktop app |
| OpenNest.Core | Domain model, geometry, CNC primitives; material-overlap diagnostics |
| OpenNest.Engine | Nesting algorithms and whole-job contracts |
| OpenNest.IO | DXF/DWG, .nest, G-code, BOM I/O; CAD import |
| OpenNest.Console | Headless batch nesting |
| OpenNest.Api / .Data | Programmatic pipeline; machine & cutting-parameter data |
| OpenNest.Gpu | GPU-accelerated pair evaluation (ILGPU) |
| OpenNest.Benchmark | Head-to-head engine comparison |
| OpenNest.Mcp | MCP server for AI tool integration |
| Posts/ | Post-processor plugins (Cincinnati CL / CI Fiber lasers, Gravograph IS8000) |
| *.Tests | Cross-platform suites; WinForms tests are Windows-only |
Nesting Engines
Engines implement INestingEngine.Solve(NestJob). Desktop Auto Nest, console autonest, MCP autonest and the API use one independent validation pipeline for every engine, including plug-ins. Invalid layouts require an explicit decision; malformed output cannot be kept. See automatic nesting and validation for caller behavior and API validation status.
| Engine | Description |
|---|---|
| Rectangles | Plain and near-rectangular plates: maximal-rectangles box packing |
| Irregular | Irregular profiles: no-fit-polygon frontier packing |
| Default | Multi-phase: linear fill → pairs → rect best-fit → extents |
| Strip | Iterative shrink-fill for mixed-drawing layouts |
| Vertical / Horizontal Remnant | Optimizes a clean remnant drop on one edge |
| StockLadder | Whole-job, stock-constrained baseline with salvage-credit ranking |
Which engine suits which jobs, renamed engine names, and the rules for changing an engine: nesting engines.
File Format
.nest files are ZIP archives containing drawing programs, metadata, plates, and placements. Saved nests retain each part's lead-ins, lead-outs, tab gaps, and locks, plus the plate's cutting settings. Changing a drawing's geometry removes obsolete cutting paths from its parts; name, quantity, and color edits preserve them. See the file-format reference for compatibility and recovery behavior.
Supported Formats
| Format | Import | Export |
|---|---|---|
| DXF | Yes | Yes |
| DWG | Yes | No |
| Excel BOM | Yes | No |
| G-code | No | Yes (post-processors) |
.nest |
Yes | Yes |
Keyboard Shortcuts
Ctrl+F fill area · F zoom to fit · Shift+wheel / middle-click rotate · X/Y push · arrows nudge · Shift+arrow push.
Status & License
Actively developed; core workflows run end-to-end from DXF import to G-code. Contributions welcome. MIT licensed — see LICENSE.