The release dialog's Add a set box was a pure type-ahead: it queried the server only after typing paused, so opening it, or clicking its arrow with nothing typed, showed an empty list. From Drawing Sets > Release that was easy to miss, but New Release starts with nothing listed, and an empty dropdown there reads as a missing server connection. The dialog now reads the first active sets by name when it is shown, and again when the list is opened while still empty, without dropping the list open on its own; typing narrows it as before. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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 — automatic multi-plate/multi-material jobs, interlocking pair evaluation, and built-in or plug-in engines. Choose an engine.
- 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 markers, and hover details through View > Overlap Check. Usage and limitations.
- Cut simulator — Plate > Simulate Cutting replays the active plate in cut order: the torch traces each cut, rapid and pierce at adjustable feed, rapid and pierce settings, with play/pause, scrubbing, 1×–250× speed and previous/next part (Page Up/Down) and cutout (Ctrl+Left/Right) jumps. Parts the torch has not reached stay greyed. It and Calculate Cut Time use separate outside and hole feeds, skip etch-only contours like the CI Fiber post, and apply the chosen machine's acceleration and corner limits from Machine Configuration (placeholder values until you enter the controller's). Timing model.
- 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.
Prebuilt Windows downloads are on GitHub Releases, or build from source to run the latest code. Release ZIPs are self-contained: extract the entire archive into a new folder and run OpenNest.exe; no separate .NET installation is needed. To update, close OpenNest and extract the new release into a new folder; ZIP releases do not auto-update (optional installer-based updates need a separately hosted Velopack feed). All nesting engines (Default, Rectangles, Irregular, Circles, FlatBar and the fill strategies) are built in; see nesting engines.
Build, Test, Run
git clone https://github.com/ajisaacs/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; CI runs it and OpenNest.FrontEnd.Tests on a GitHub-hosted Windows runner for every master push and pull request.
Quick start
- File > New
- Import DXFs via the CAD Converter (layer/color filtering, per-entity exclude and cut/etch/display-only roles, 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
dotnet run --project OpenNest.Console -- job.nest --no-fill --plan-cutting --all-plates
| Option | What it does |
|---|---|
--size WxL |
Set the plate size; required for DXF-only input. |
--autonest |
Run validated whole-job nesting; one sheet unless --max-sheets <n> allows more. |
--engine <name> |
Choose a whole-job engine with --autonest, or a fill strategy without it. |
--quantity <n> |
Limit parts placed (0 means unlimited). |
--spacing <value> |
Override part spacing. |
--template <path> |
Read plate defaults from a nest file. |
--output <path> |
Set the output nest path. |
--check-overlaps |
Check the result for overlaps. |
--no-fill |
Keep a loaded nest as it is, for example to plan cutting or post it. |
--plan-cutting |
Plan and apply cutting (part order, contours, entries, lead-ins); see cut planning. |
--cutting-params <path> |
Cutting settings JSON for --plan-cutting; otherwise the plates' saved settings are used. |
--post <name> |
Run a post-processor after nesting. |
--no-save |
Skip saving the nest. |
--allow-invalid |
Explicitly keep a representable invalid --autonest result; otherwise it is rejected. |
Run dotnet run --project OpenNest.Console -- --help for the complete options and their defaults.
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
Default compares the built-in Irregular, Rectangles and Circles engines and keeps the best valid whole-job layout. Other engines and plug-ins suit particular jobs; see which engine to use. Desktop Auto Nest, console autonest, MCP autonest, and the API share an independent validation pipeline, including for plug-ins. Automatic nesting and validation explains how callers handle invalid results.
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.

