SolidCraft: An Open-Source, Clean-Room Fusion 360 Rebuilt in Pure Rust — and AI Agents Can Drive It

Tangency Labs released SolidCraft, an open-source, clean-room reimplementation of Autodesk Fusion 360 written in pure Rust, with an MCP server that lets AI agents drive the same commands as the desktop app, browser app, and headless CLI. The project reports that 75 of 76 public reference parts match their analytic or FreeCAD-computed volume, area, center of mass, and bounding box, with the one holdout a tracked bug, and it is dual-licensed MIT OR Apache-2.0. SolidCraft describes itself as "early but usable for simple parts" and is unaffiliated with Autodesk, offering STEP, IGES, 3MF, STL, OBJ, glTF, and URDF export plus parametric features, assemblies, and sheet metal.

SolidCraft: An Open-Source, Clean-Room Fusion 360 Rebuilt in Pure Rust — and AI Agents Can Drive It Professional parametric CAD has long been a walled garden: Fusion 360, SolidWorks, Onshape, Creo — powerful, expensive, proprietary, and utterly closed to automation beyond their own scripting APIs. SolidCraft https://github.com/tangency-labs/solidcraft sets out to break that open. It’s an open-source, clean-room reimplementation of Autodesk Fusion 360, written in pure Rust — and it was built so AI agents can drive it natively. Real Parametric CAD, Not a Toy This isn’t a block-stacking Tinkercad clone. SolidCraft has the machinery that makes professional CAD actually useful: - Sketches and constraints — lines, arcs, splines, text, solved by their own constraint solver, with parameter-driven dimensions. - Features on an editable timeline — extrude, revolve, sweep, loft, fillet, chamfer, shell, draft, holes, threads, patterns, mirror, split, combine. Change a dimension upstream and the whole model rebuilds. - Parameters and configurations with unit-aware expressions. - Assemblies with joints, motion studies, contact sets, interference checks, and mass properties. - Sheet metal flanges, hems, fold/unfold, flat patterns and plastic enclosure features. - File I/O — STEP, IGES, 3MF, STL, OBJ, glTF, plus URDF export for robotics. The demo says it all: a Raspberry Pi 4 case modeled from scratch — sketch dimensioned to the board, extrude, fillet, shell, M2.5 standoffs patterned on the 58×49 mm hole rectangle, port cut-outs, vent slots, “Pi 4” engraved in DejaVu Sans Bold, PETG material with computed mass — then bump height 24→32 mm in Parameters and everything rebuilds. That’s genuine feature-based parametric CAD. The Agent-Native Part Here’s what makes SolidCraft worth writing about on this blog: the desktop app, browser app, headless CLI, and MCP server all run the same commands. The MCP server solidcraft-cli mcp means an AI agent models parts the exact same way the UI does. Headless, it spins up its own design session; with --connect , it drives the running app so you can watch it build in real time. One line wires it into Claude Code: claude mcp add solidcraft -- solidcraft-cli mcp This is the same philosophy we keep flagging as the real shift — software designed from the ground up to be operated by AI agents https://themenonlab.blog/free-my-tv-claude-code-ad-free-smart-tv-home-screen/ , not just wrapped in a chatbot afterward. And it pairs naturally with the generative-3D work we’ve covered, like turning a single photo into a relightable 3D asset https://themenonlab.blog/supra-tex-single-image-3d-relightable-pbr-texture/ : SUPRA-Tex gives you organic, textured meshes, while SolidCraft gives you precise, dimensioned, manufacturable parts an agent can parametrically adjust. Verified, Not Just “It Runs” I appreciate teams that are honest about maturity. SolidCraft calls itself “early but usable for simple parts” and backs it with evidence: 75 of 76 public reference parts match their analytic or FreeCAD-computed volume, area, center of mass, and bounding box — the one holdout is a tracked bug. Geometry is checked against an “oracle” of real values, not assumed correct because the code compiled. That’s the right instinct for CAD, where a silently wrong fillet means a part that doesn’t fit. The Legal Angle Cloning a commercial product invites lawyers, so SolidCraft is explicit: it’s a clean-room implementation, designed from public documentation and general CAD conventions, independent and unaffiliated with Autodesk or any vendor, developed under documented clean-room contribution rules. Dual-licensed MIT OR Apache-2.0. Why It Matters An open, scriptable, agent-drivable parametric CAD kernel is a genuinely big deal. It means reproducible, version-controllable designs; parts generated and iterated by LLMs; and CAD that runs in CI, in the browser, or on a Raspberry Pi — no seat license, no cloud lock-in. For hardware startups, makers, and anyone building AI-driven design tools, this is foundational infrastructure finally going open. Try it in the browser, grab a desktop build, or point an agent at it. Repo: github.com/tangency-labs/solidcraft https://github.com/tangency-labs/solidcraft · Website: solidcraft.io https://solidcraft.io · Browser app: solidcraft.io/app https://solidcraft.io/app · Docs: docs.solidcraft.io https://docs.solidcraft.io/