SolveCraft
Parametric 3D CAD; an open-source, clean-room reimplementation of Autodesk Fusion 360, built in pure Rust.
Sketch, constrain, and build solids with a parametric feature timeline. Change a dimension and watch your model rebuild. Run it on your desktop, in your browser, or let AI agents model through the built-in MCP server. Part of the storytold "craft" family.
An agent builds an electronics enclosure over MCP: sketches on faces, shell, a port cut, one screw boss patterned to four, then width 80 → 100 mm in the Parameters dialog and the timeline rebuilds. 3× speed; full video, script in examples/demo.
Documentation: the SolveCraft book (user guide, developer guide and command reference; sources in docs/book), and the web app to try it in the browser.
Status: early but usable for simple parts. 76 of 76 reference parts built in Fusion rebuild in SolveCraft with the same volume, area and topology (docs/oracle.md); command parity with Fusion's Design workspace is tracked in docs/parity.md. Open work and known bugs are in GitHub issues, and help is welcome: see CONTRIBUTING.md.
What works
- Sketches on origin planes, offset planes or planar faces: lines, rectangles, circles, arcs, polygons, slots, ellipses, fit/control splines, conics and text; construction geometry, projection, trimming, fillets and chamfers, including corners at the origin. New face attachments retain supported construction identities and chosen occurrences; missing sources expose an explicit plane repair workflow. See face attachments. Explicitly closed fit splines and closed associative offsets use periodic C2 interpolation.
- Constraints and dimensions solved by our own solver (damped Gauss–Newton with degree-of-freedom analysis): coincident, horizontal/vertical, parallel, perpendicular, tangent, equal, concentric, collinear, midpoint, symmetry, fix; linear, aligned, horizontal, vertical, radius, diameter and angle dimensions driven by parameters. Over-constraining edits are rejected; fully constrained geometry turns black.
- Profiles found automatically, including regions split by lines and holes inside outlines.
- Features on a parametric timeline: extrude, revolve, sweep, loft, fillet/chamfer, shell, draft, holes, threads, patterns, mirror, split, combine, move and construction geometry. The timeline rebuilds incrementally; features can be edited, suppressed, renamed, reordered and deleted. Supported geometry and current limitations are described in ROADMAP.md. New revolves preserve symmetric and two-sided angular placement across reversed axes; older designs retain their saved convention when reopened or edited.
- Parameters and configurations with unit-aware expressions (
2 * width + 5 mm,angle / 2), ordered rules, feature suppression and per-row body materials/appearances. - Assemblies with nested components and occurrences, joints, motion studies, contact sets, interference and material-aware mass properties. Recorded body transfers preserve modelling history and world placement; 3D sketch wires retain their coordinate frames through edits.
- Sheet metal with flanges, hems, fold/unfold/refold, material cutouts, flat patterns, retained shallow prismatic pockets, exact line/arc/circle DXF outlines and bend tables; plastic enclosure features and rules. Pocket depth and side survive unfold/refold and appear separately from through-hole outlines in the flat preview and DXF.
- Files: designs as JSON (
.solvecraft), export to STEP (AP242 with body names, colours and components as assemblies; revolved faces as native planes, cylinders, cones, spheres and tori), IGES 5.3 (manifold solid B-reps with names and colours), 3MF, STL (binary/ASCII) and OBJ; 3MF, STL and OBJ import as mesh bodies (they render, measure, move and export; solid features need B-rep bodies); STEP import (AP203/AP214/AP242 solids, assemblies, units, names, colours) and IGES import (manifold solid B-reps, or trimmed and bounded surfaces sewn into solids) as a base feature that later features build on — open a.step/.stp/.igs/.igesfile, insert one into a design, or drop it on the window (docs/step-import.md). - Desktop app (egui + wgpu): toolbar with workspace tabs, browser, timeline, 3D viewport with view cube and navigation bar, sketch tools, feature dialogs, command palette, and a JSON-lines control channel so agents and tests can drive it.
- Headless CLI
solvecraft-cli: run command scripts, measure (volume, area, centre of mass, face/edge/vertex counts), export, render PNG snapshots, replay Fusion oracle recipes. - MCP server
solvecraft-cli mcp: AI agents model, measure and look at parts headless or in the running app (see below).
Build and run
cargo run --release -p solvecraft -- --sample # desktop app with a sample part
cargo run --release -p solvecraft-cli -- commands # the command registry
cargo run --release -p solvecraft-cli -- run examples/bracket.json --out bracket.step
cargo run --release -p solvecraft-cli -- snapshot examples/bracket.json --out bracket.png
cargo run --release -p solvecraft -- part.step # open a STEP file as a new design
cargo run --release -p solvecraft-cli -- eval part.step # measure an imported STEP file
cargo xtask ci # fmt, clippy, tests, assets, layers, wasm
Windows builds: cargo xwin build --release --target x86_64-pc-windows-msvc -p solvecraft.
In the browser: cd apps/solvecraft-web && trunk build --release --public-url ./ (WebGPU, or
WebGL2 with ?webgl; ?sample opens the sample part).
Scripts
A script is a JSON list of commands, the same ones the UI runs:
{"commands": [
{"command": "sketch.create", "params": {"plane": "XY"}},
{"command": "sketch.rectangle.two_point", "params": {"p0": [0, 0], "p1": [40, 30]}},
{"command": "solid.extrude", "params": {"distance": 20}},
{"command": "solid.fillet", "params": {"edges": [[0, 0, 10]], "radius": 3}}
]}
AI agents (MCP)
solvecraft-cli mcp is a Model Context Protocol server on
stdio. Headless it runs its own design session; with --connect 127.0.0.1:PORT it drives the app
started with solvecraft --control PORT, so you can watch the agent model. Tools:
list_commands, execute, batch, inspect_design, measure, body_topology,
set_parameter, screenshot (returns the image), export, undo, redo, new_design, open,
save. Claude Code: claude mcp add solvecraft -- solvecraft-cli mcp. Details, client
configuration and an example session: docs/mcp.md.
Architecture
| Layer | Crates | Role |
|---|---|---|
| L0 | geom |
vectors, planes, profiles, meshes and their measures |
| L1 | sketch, kernel, render |
constraint solver and profiles; the B-rep kernel boundary (truck); view math and CPU rasterizer |
| L2 | doc |
parameters, expressions, the feature timeline and its incremental evaluation |
| L3 | io |
design files, STL/OBJ/STEP/3MF export, STEP and 3MF/STL import features |
| L4 | engine |
the session and the command registry (everything is a command) |
| L5 | ui-egui, mcp |
the swappable desktop front end; the MCP server (headless or bridged to the app) |
| apps | solvecraft, solvecraft-cli |
desktop app, headless CLI |
Contributing
See CONTRIBUTING.md: how to build and test, the code map, the clean-room and licence rules, and where help is wanted most.
Licence
MIT OR Apache-2.0, at your option. SolveCraft is not affiliated with Autodesk; Fusion is a trademark of Autodesk, Inc.