Millwright
Open-source AI automation layer for SolidWorks: talk to your CAD in plain language.
What it does and how it connects
Millwright is an open-source AI workbench that drives SolidWorks directly instead of generating macros for the user to paste and run. It calls about 50 native SolidWorks tools, covering sketch, feature, assembly, export and query operations, one step at a time, with each call returning a structured result the AI reads before deciding its next move. The README's position is that the AI operates SolidWorks, not just writes code.
The runtime is dual-engine: a Python sidecar talks to SolidWorks over early-bound COM, and if the sidecar cannot start, Millwright falls back to a built-in VBScript engine and says so in the chat. SolidWorks versions are handled adaptively at runtime, with signature discovery and dynamic dispatch, because the COM API shifts across releases. A visual feedback loop lets the AI screenshot the model and reason over it before moving on.
Safety is built into the flow: destructive operations show a confirmation card with the tool name and full parameters and require a click, documents are backed up automatically before destructive edits, and CAD files never leave the user's machine, with only text sent to the AI provider. The user chooses the AI backend, such as Claude, GPT, DeepSeek, Kimi, MiniMax, Qwen, GLM or a local Ollama model, and pays only for their own API usage.
What engineers report
Bug report on issues encountered during use; the body lists environment details and links an external document.
2026-08-02Read the original
Alternatives
Compare side by side- Vulcan
A SolidWorks AI add-in that turns natural language into an editable JSON feature tree executed by a C# add-in, rather than a workbench that drives SolidWorks through direct native tool calls.
- MecAgent
A commercial desktop copilot that acts inside the open SolidWorks session, rather than an open-source workbench the user runs with their own model key.
Recurring errors it addresses
Error Index entries this tool is built to reduce or work around.
- Saving an assembly can trigger rebuilds that break mates and randomly alter mate dimensions.Error Index
- Large assemblies can lock up on open with the feature tree failing to populate.Error Index
- Even simple save/check-in operations can take minutes on capable hardware.Error Index
- A shipped SolidWorks agent skill called interference-check API methods that do not exist (InterferenceDetection, GetInterference(index), GetComponents) and called Done() before computing, so its core validation step could never complete on a real machine. The check silently never ran.Error Index
- A SolidWorks MCP bridge returned success JSON and even a normal-looking PDF export while the live document was wrong: a sketch asked for the Right plane silently landed on Front, and a macro call reported success=False with zero errors while never running. Only visual inspection inside SolidWorks itself revealed it.Error Index
Sources
Not verified
- A named individual builder beyond the repository owner handle raylanlin
Last verified November 6, 2026. Listings are informational. The evidence score measures public, verifiable evidence and is not an endorsement or a compatibility claim.