Nest windows now rerun the overlap check once the layout has been unchanged for 0.5 s, instead of leaving 'Overlaps: not checked'. Edits show 'Overlaps: check pending...'; drags are caught by the paint-time pose stamp, collection edits by their events. The check waits while a mouse button, modal dialog or fill is active, supersedes a running check when the layout moves again, and does not retry a canceled or failed layout until it changes. Rechecks use the incremental analyzer, so only the moved parts' neighbors are recomputed. Automatic results update only the canvas label (the status bar keeps the last command's message) and keep Display > Off. Check Active Plate still runs immediately. InvalidateOverlapCheck now also drops cached material.
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 package includes the Gpt6Astra, Opus55, and Qwen38FlashNext engine plug-ins. 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 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 (whole-job nesting), --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. Community engines live in OpenNest-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
Jobs-only API: engines implement INestingEngine.Solve(NestJob); only NestJobRunner commits demand and stock, and every candidate passes the placement validator (bounds, spacing, rotation policy, stock match) before it consumes anything.
| Engine | Description |
|---|---|
| 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 |
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.

