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

1. File > New
2. 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
3. Define plate size, material, quadrant, spacing
4. Fill — the engine arranges parts
5. 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.