cadrs

A parametric, feature-based CAD app written in Rust, with a Bevy UI and its own pure-Rust B-rep modeling kernel. Its workflow is sketch on a plane, constrain and dimension, build parts from features, put them together in assemblies, and make drawings from them.

• Sketching: lines, rectangles, circles, arcs, splines, Bézier curves, ellipses, polygons, slots, points and text. Snapping and inference to points, midpoints, centres, intersections, alignments and part edges. Geometric constraints and driving dimensions, with a least-squares solver that keeps the sketch consistent while you drag. Trim, extend, split, offset, mirror, patterns, and Use (project) of part edges.
• Part Studios: extrude, revolve, sweep, loft, fillet, chamfer, shell, draft, hole (counterbore, countersink, tapped; ISO and ANSI tables), linear and circular patterns, mirror, booleans, Transform, planes, mate connectors, thicken, fill and helix. Every feature can be edited later, and the part rebuilds.
• Assemblies: instances, fastened, revolute, slider, cylindrical, planar and other mates, a triad to move parts, mate connectors, exploded views and a bill of materials.
• Drawings: standard and projected views, sections, dimensions, annotations, callouts and BOM tables.
• More: versions and history, derived parts and linked documents, a variable table and expressions, measurement and mass properties, linear static simulation (FEA), a path-traced renderer, PCB Studio with IDF import and export, and STEP, IGES and STL import and export.
• Drag and drop: drop SVG, EPS, PDF, DXF or DWG drawings onto a Part Studio or an open sketch to get editable sketch curves, pictures to place them, and STEP, IGES or STL models to import them (EPS and PDF need Ghostscript and Poppler installed).
• Onshape import: bring your own Onshape documents across with their feature history instead of dead STEP geometry (tools/onshape).
• AI assistants (MCP): So an AI assistant on your machine (Claude Code, Claude Desktop, Cursor, …) can drive the running app: create documents, draw sketches, add and edit features, read back faces and edges, export STEP and take screenshots. Turn it on in Preferences › AI assistants (MCP); the app then serves Streamable HTTP on http://127.0.0.1:7680/mcp (loopback only; the port is a preference). Every tool call runs through the command layer, so the assistant's steps show in the feature list and undo like your own. The repository's .mcp.json registers the server with Claude Code for this project (approve it with /mcp the first time; claude mcp list shows whether it is connected). Elsewhere, claude mcp add --transport http cadrs http://127.0.0.1:7680/mcp does the same, and other clients take the URL in their MCP settings.

Codebase

Crate	What it is
cadrs	The binary: command-line flags, windowed or headless
cadrs_app	The app's Bevy plugins: documents page, tabs, viewport, tools and dialogs
cadrs_ui	A reusable Bevy widget library (theme, buttons, inputs, menus, dialogs, lists)
cadrs_core	The document model, features, rebuild, commands and undo, persistence (no Bevy)
cadrs_sketch	Sketch geometry, constraints, the solver, snapping and hit testing (no Bevy)
cadrs_kernel	The B-rep modeling kernel (pure Rust) and its API, with persistent face and edge names
cadrs_drawing	Drawing views, projection and annotations
cadrs_fea	Linear static finite-element analysis
cadrs_render	A CPU path tracer for photorealistic renders
cadrs_idf, cadrs_pcb	IDF files and PCB boards
cadrs_harness	Scripted scenarios, synthetic input and screenshots
cadrs_mcp	The MCP server through which AI assistants drive the app

Tests

cargo test -r -p cadrs_core --test reference_parts -- --nocapture

Sponsors

Thank you to:

Sponsor cadrs on GitHub.