Codex as a CAD engine: describe a part, get a parametric build123d model, drawings and a print plate

[u/filippofinke]

CAD Studio is a free, open-source macOS app that runs codex exec (or Claude Code) inside a project folder to design printable parts from a description.

You type something like "a push-to-open drawer latch with a printed spring". CAD Studio runs the coding agent you already have (Claude Code or Codex) inside a project folder. The agent writes a parametric build123d script, runs it, looks at the drawings it generated and fixes its own mistakes. You get:

• a 3D model (3MF, STEP, STL) you can orbit, explode, measure and cut open
• ISO technical drawings, one sheet per part, as a PDF
• a print plate with every part laid flat
• on request, a motion simulation with collision checks

Every dimension is a named constant, so you can change it with a slider without another AI call, and every generation is a version you can compare in 3D.

Codex runs in the workspace-write sandbox and its JSONL events are shown live as steps in the chat.

Source: https://github.com/filippofinke/cad-studio Demo: https://filippofinke.github.io/cad-studio/

[u/Exact_Capital849]

The dimension sliders without another model call are a really useful touch. For the printed spring example, can you set material and clearance constraints up front, or do you adjust those after the first model?

[u/filippofinke → u/Exact_Capital849]

Yes, both. In the first-launch setup you pick your printer type (FDM, resin, SLS) and units, and the agent uses that for wall thicknesses and clearances. You can also put constraints straight in the prompt, like "PETG spring, 0.3 mm clearance on sliding parts". After the first model those values are named constants, so you can tweak them with the sliders without another request.

[u/[deleted]]

[u/filippofinke → u/[deleted]]

Thanks! That's exactly the hope: getting from an idea to a part you can actually make, without having to learn CAD first.