freecad-chatcad
AI agent side panel for FreeCAD: model parametric parts by chatting with Claude.
What it does and how it connects
Chat CAD for FreeCAD is an AI agent side panel docked inside FreeCAD. Describe a part, point at a face, or scribble on the 3D view, and an agent models it as a parametric FreeCAD document you can keep tweaking by hand. It works with Claude Code, OpenAI Codex, Google Antigravity, or a local model through Ollama or any OpenAI-compatible server. Dimensions live in a Parametros spreadsheet with aliases, so changing a number and pressing Ctrl+R updates the part. Status is alpha, tested on Windows 11 with FreeCAD 1.1.4; Linux and macOS should work but are untested, and the interface is in Brazilian Portuguese.
Safety nets include a backup copy before changes, one undo entry per local-agent step, and automated checks that verify each result. The README is candid about local models: in its tests every real multi-feature part failed with local models, even one feature at a time, while Codex was the fastest and most faithful cloud agent in a timed comparison, taking 6 min 21 s with a volume within 0.04 percent of the reference part.
Agents run Python code inside the user's FreeCAD session with the user's permissions. CLI agents are sandboxed: Codex runs with a read-only sandbox, Claude Code loads only the freecad MCP server, and Antigravity allows only mcp(freecad/*). The panel talks to FreeCAD through the freecad-mcp server by neka-nat.
Alternatives
Compare side by side- freecad-ai (josheeg)
An MCP server that drives FreeCAD 1.1 headlessly over an XML-RPC bridge, rather than a chat panel docked inside FreeCAD.
- OmniCAD
A standalone free parametric CAD app with its own MCP server and CLI, rather than a panel inside FreeCAD.
- Text23D Mechanical
Turns chat prompts into CadQuery or FreeCAD models in a web workbench, rather than a panel inside the FreeCAD GUI.
- Sphaire
Browser-native parametric CAD on OpenCascade through WebAssembly, rather than a panel inside FreeCAD.
- cad-agent-foundation
An AutoCAD MCP and CLI on the native .NET API, rather than a FreeCAD agent panel.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- When an agent fans out parallel create calls through the FreeCAD MCP bridge, the shared connection races: the first object is created even though its call reports failure, and the second object is silently never created with the status still showing healthy.Error Index
- A FreeCAD MCP bridge silently ignored parameters the client materialized from JSON-Schema defaults, so box(size=20) produced a default 10mm shape. The agent believes it built the requested geometry while the model is something else entirely.Error Index
- A FreeCAD MCP bridge's autosave-before-call rewrote the active document on every tool call even with zero unsaved changes, stamping phantom diffs onto git-tracked CAD files. Agent activity pollutes version control with edits no human authored.Error Index
- A FreeCAD MCP bridge's persistent execution namespace meant that once any call bound a variable named result, every later call echoed the old value as its own output. The agent reads that output and believes its code produced a value it never computed.Error Index
- A FreeCAD MCP bridge reported clean instance shutdowns as failures 100 percent of the time on Linux, because its liveness check polled immediately after signaling the process group. The agent was sent to retry or kill processes that were already gone.Error Index
Sources
Not verified
- Pricing: none stated on the repo.
- Real user voices: no real linked post read for this page; the repo has no public issues.
- No GitHub releases exist, so latest release fields are null.
- A standalone website: the repo homepage points to the author's portfolio, not a product site.
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.