Cookbook — Qwen-MM-Plugins FreeCAD

Driving a real, running FreeCAD from a prompt with qwen-mm-plugins-freecad: the model builds a parametric part, cuts geometry with booleans, and exports STEP/STL. See the Cases below. (For 3D modeling / rendering, see cookbooks/blender.)

This capability talks XML-RPC to a running FreeCAD carrying the bundled FreeCADMCP addon. You don't start it by hand — after installing, the first query brings it up automatically (on Linux it also auto-downloads the app if missing). It needs no API key.

Tools

Documents

• create_document, list_documents, reload_document

Objects

• create_object, edit_object, delete_object, get_object, get_objects

Parts library

• get_parts_list, insert_part_from_library

Views & code

• get_view — screenshot a named standard view
• execute_code, execute_code_async — run Python in FreeCAD

FEM

• run_fem_analysis — run a finite-element analysis (needs CalculiX)

For exact schemas, check the installed Skill or the MCP tool list.

Install

claude plugin marketplace add https://github.com/QwenLM/Qwen-MM-Plugins.git
claude plugin install qwen-mm-plugins-core@qwen-mm-plugins
claude plugin install qwen-mm-plugins-freecad@qwen-mm-plugins

On a headless server (a cloud host / SSH with no display), one extra step (needs root):

sudo apt install xvfb

Skip this on a desktop with a real display.

For Codex and other harnesses, use the guided installer. Harness-specific Skill + MCP registration is covered in Manual harness setup.

Environment variables (usually none needed)

On non-Linux-x86_64 platforms (auto-download only covers Linux-x86_64), install FreeCAD 1.1.x yourself and put it on PATH, or point at it with FREECAD_BINARY.

Set these via env vars, ~/.qwen-mm-plugins/config, or the guided installer bash install.sh (bash install.sh verify checks what's set).

Cases

Case 1 — parametric L-bracket, exported, then re-driven from its parameters (Claude Code)

Model a parametric L-bracket: 80×60 mm, 8 mm thick, with two 6 mm mounting holes in each flange.
Show me an isometric view, then export STEP and STL to exports/.
Then change the bracket's thickness to 12 mm and the hole diameter to 8 mm, re-verify, and
re-export. Finally read the exported STL back with the core plugin's visualize tool, so we can see
the exported geometry independently of FreeCAD's own view.

10 tool calls: list_documents (empty) → create_document → 5 × execute_code → get_view Isometric → core's visualize. Every dimension is bound by expression to a Spreadsheet::Sheet, so the 8 → 12 mm thickness and 6 → 8 mm hole change is two cell edits plus a recompute.

Case 2 — parametric dovetail camera quick-release plate (Codex)

Model a parametric camera quick-release plate: 100 x 42 x 10 mm, with a dovetail rail profile,
two elongated mounting slots, a centered 1/4-20 clearance hole with counterbore, raised lips
around the slots, and a rear stop block. Put the driving dimensions in a Spreadsheet::Sheet and
bind the geometry to those cells by expression, so that editing a cell and recomputing actually
updates the part. Export FCStd/STEP/STL and an isometric PNG to cookbooks/freecad/assets/ as
freecad-codex-dovetail-quick-release.{FCStd,step,stl,png}. Then change the top dovetail width,
slot width, and stop height by editing the spreadsheet cells, recompute, verify the shape is still
a single valid solid and report its bounding box and volume, and re-export.

Work only through the qwen-mm-plugins-freecad MCP tools. Do not use shell commands.

The part is a Part::FeaturePython object whose 13 driving properties are all bound by expression to a Spreadsheet::Sheet, which get_object reads back from the ExpressionEngine — so the parametric claim is checkable in the trace. First build: one valid solid, 100 × 42 × 18 mm, 37 467.93 mm³. After editing three cells and recomputing: still one valid solid, now 100 × 42 × 22 mm and 36 481.58 mm³.

Case 3 — ask a GUI harness to install FreeCAD support (QoderWork)

The agent is asked to install the freecad plugin from this repository:

Troubleshooting

• Can't connect / first call is slow: the first call downloads FreeCAD (~1 GB) in the background and starts it — wait 1–2 min; subsequent queries connect instantly. For manual or source-checkout launch commands, see the Skill.
• Headless machine reports xvfb errors: sudo apt install xvfb (needs root). Not needed with a real display.
• FEM won't run: it needs the CalculiX solver: sudo apt install calculix-ccx.

Attribution & License

• freecad is ported from neka-nat/freecad-mcp (MIT)

Full third-party licenses are in the capability's NOTICE.md.