neoscad

NeoSCAD

NeoSCAD is a new implementation of the OpenSCAD language, written in Rust. It runs your .scad files and libraries as they are, renders with Manifold, and adds a surface built for people and for AI agents: structured JSON output, check, measure and snapshot, an MCP server, a language server and a long-running serve mode.

NeoSCAD extends OpenSCAD with three language extensions, all off by default so that a file means exactly what it means in OpenSCAD: named parts (part("lid") { ... }, --enable part), which check and measure report on one by one and SVG and DXF exports keep apart; constrained 2D sketches (sketch() { ... }, --enable sketch): points, lines, arcs and circles tied by constraints and solved into a 2D shape, as in FreeCAD's Sketcher (docs/sketch.md); and geometry queries (--enable query): a module can read its children's bounding box, volume and area (child_bounds(), child_measure()) or the points they name (anchor(), child_anchors()) as ordinary values (docs/geometry-queries.md). A fourth switch, --enable exact, exports STEP whose faces are the model's true planes, cylinders, cones, spheres and tori, for CAD programs such as FreeCAD, from the command line, the apps, the MCP server and the browser (docs/step-export.md). A fifth, --enable fillet, rounds or bevels chosen edges of any solid, boolean results included, with CadQuery-style selectors (fillet_edges(r = 2, edges = "|z") cube(...)), as FreeCAD's and CadQuery's fillets do, and exports them as exact cylinders, tori and cones with --enable exact (docs/fillet-edges.md).

Libraries such as BOSL2 can be project dependencies: neoscad add BOSL2 --git https://github.com/BelfrySCAD/BOSL2 --tag v2.0.716 records them in scad.toml, pins each to a commit and a content hash in scad.lock, checks every revision out once per machine into a shared store and links it into the project, so include <BOSL2/std.scad> finds the pinned copy with no change to the source. neoscad vendor copies them into a plain folder for stock OpenSCAD (docs/dependencies.md).

• Website: https://neoscad.org
• Try it in the browser: https://neoscad.org/try

Status

NeoSCAD is pre-release. As of the final v0.1 audit (docs/audits/final.md):

• Conformance: it passes all 1,773 of OpenSCAD's in-scope regression tests (conformance run; the ids are in conformance/baseline.json). Out of scope are the CGAL-only, experimental, known-bug and upstream-disabled cases.
• Speed: about 2.8× faster than the OpenSCAD nightly (Manifold backend) on heavy models. The method and the numbers are in docs/audits/final.md and on https://neoscad.org/benchmarks.html. To time a release on your own machine, against your own OpenSCAD, and share the result, run neoscad bench (docs/community-bench.md).

Platforms and install

• macOS (Apple silicon and Intel): the app and the neoscad command line.
• Linux and Windows (x86_64 and ARM64): the command line. Windows builds are unsigned; verify them with gh attestation verify.
• Browser: a WebAssembly demo at https://neoscad.org/try.

Releases: https://github.com/neoscad/neoscad/releases, with every way to install on https://neoscad.org/download.html. For example brew install neoscad/tap/neoscad (the command line) or brew install --cask neoscad/tap/neoscad-app (the macOS app).

Each desktop app carries its own neoscad for AI agents to run (docs/mcp.md, "Setup from the apps"): inside NeoSCAD.app on macOS, as bin\neoscad.exe in the Windows install folder, and as flatpak run --command=neoscad org.neoscad.NeoSCAD from the Flatpak. None of them puts it on PATH; for the terminal, install the command line on its own.

neoscad lsp --stdio is the language server for other editors; setting it up in VS Code, Neovim, Helix and Emacs is in docs/lsp.md.

Build from source

You need a Rust toolchain (rust-toolchain.toml pins it). The conformance suite also needs OpenSCAD's test data, from a checkout at .reference/openscad:

git clone --depth 1 https://github.com/openscad/openscad.git .reference/openscad
git -C .reference/openscad submodule update --init --depth 1 libraries/MCAD

Then:

cargo build --release
cargo fmt --all && cargo clippy --all-targets -- -D warnings && cargo test
./target/release/conformance run [--tier N] [--filter S] [-v]
./target/release/neoscad --help

The macOS app:

scripts/apple/build-core.sh                    # Rust core -> XCFramework + Swift bindings
xcodegen generate --spec apple/project.yml     # apple/NeoSCAD.xcodeproj
xcodebuild -project apple/NeoSCAD.xcodeproj -scheme NeoSCAD -derivedDataPath apple/build/DerivedData build

The web demo is in web/ (see web/README.md); scripts/wasm-check.sh builds the library crates for wasm32 and runs them in Node.

CLAUDE.md lists every build, test and benchmark command, and docs/architecture.md describes the design.

Support

NeoSCAD is free and open source. If it's useful to you, you can support its development at givebutter.com/neoscad. Donations go to The Ned Workshop, a 501(c)(3) nonprofit, and are tax-deductible in the US to the extent the law allows. Donations pay for what shipping it costs: the Apple Developer Program for the signed macOS app, the domain, and time on the engine and the apps.

Licence

NeoSCAD is licensed under the GNU General Public License, version 2 or later (GPL-2.0-or-later; see LICENSE). Third-party notices are in NOTICE.

Some dependencies, such as manifold-rust (vendored in vendor/), are licensed under Apache-2.0 only. The Free Software Foundation considers Apache-2.0 compatible with GPLv3 but not with GPLv2, so distributed NeoSCAD binaries, which combine the two, are effectively under GPLv3 (or later; see the FSF's licence list). The source files themselves remain GPL-2.0-or-later.

The dependency manager, scad-deps, is NeoSCAD's own crate in its own repository (neoscad/scad-deps), MIT-licensed so that tools under any licence can share its formats and store. It depends on nothing under the GPL, and its notice ships with the binaries (packaging/licenses/).

Credits

NeoSCAD would not exist without OpenSCAD: its language, its behaviour and its regression tests are the specification NeoSCAD is built against. Geometry is computed with Manifold, through a Rust port. Bundled fonts and libraries are credited in assets/README.md.

Built by The Ned Workshop (Matt Robinson); built with Claude.