SolidCraft (tangency-labs)
Open source parametric 3D CAD in Rust that runs on desktop and web and lets AI agents drive it through MCP.
What it does and how it connects
SolidCraft is an open-source parametric 3D CAD application built in pure Rust. Users sketch, constrain and build solids with a parametric feature timeline, change a dimension and watch the model rebuild, and run it on the desktop, in the browser, or through the built-in MCP server. Downloads are offered for Windows, macOS and Linux, plus the Snap Store and a browser app.
For AI agents, solidcraft-cli mcp is a Model Context Protocol server. Headless, it runs its own design session; with --connect it drives the running app so the user can watch. Desktop app, browser app, headless CLI and MCP server all run the same commands, and designs are .sc files, with .solidcraft files from earlier releases still opening.
The README shows modelling a Raspberry Pi 4 case from an empty design: a sketch dimensioned with parameters, extrude, fillets and shell, a rim rounded in one pick, and standoffs patterned on the board's mounting holes. The repo is very active, with thousands of issues and pull requests, and the latest release at research time is the v0.40.0 release candidate.
What engineers report
Loading a part, finding its center and trying to cut a circle fails with a boolean cut error and no result.
2026-11-07Read the original
Alternatives
Compare side by side- OpenCADStudio
A Rust CAD program for 2D and 3D drawing with DWG and DXF support and an MCP endpoint, rather than a parametric 3D CAD application in Rust.
- OpenGeometry
A browser-native CAD geometry kernel for web apps and AI CAD, rather than a full parametric 3D CAD application.
- synaps-cad
A 3D CAD IDE that edits code, visualizes in 3D and reshapes designs with natural language, rather than a parametric 3D CAD application with a feature timeline.
- freecad-mcp (blwfish)
An MCP server exposing FreeCAD modeling, CAM and diagnostics to agents, rather than a parametric 3D CAD application with a built-in MCP server.
- text-to-cad
A text-to-CAD plugin and skills set that generates CAD geometry from prompts, rather than a parametric 3D CAD application with a built-in MCP server.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- A STEP export from SolidCraft lost the side faces on 3 of 4 tapered legs when opened in other CAD tools, leaving only end discs. SolidCraft read its own file back fine; the fault was which ring of the cone face the loop started on, which other readers depend on.Error Index
- After a shell on a tapered, filleted box, four inner corner fillet edges miss their surface by up to 0.0198 mm. SolidCraft shows the body and re-imports it without complaint; FreeCAD 1.1.4, used as an outside reader, flags the four faces as invalid.Error Index
- Booleans on lofted B-spline bodies are 1 to 2 orders of magnitude slower than on prismatic bodies, and a join between bodies sharing faces of the same loft fails after 5 min 11 s with 'no result', while the same part builds fine in FreeCAD/OCCT.Error Index
- Two hand-typed file-open lists fell behind the format registry, so the web picker misses IGES and Start and Import misses FreeCAD and Rhino files even though the app reads both.Error Index
- An extrude cut on a big CadQuery STEP of a brick facade with thousands of faces takes about 140 seconds in SolidCraft.Error Index
Sources
Not verified
- Pricing: none stated on the repo; the application is free open source.
- License: the repo carries both LICENSE-APACHE and LICENSE-MIT files and the GitHub API reports Apache-2.0, so the dual license MIT OR Apache-2.0 is recorded.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.