10 CAD-generation systems under test

Four mechanical engineers (median 9 yrs CAD experience) modelled the same prompts in Onshape. Wall-clock time and tool cost ($/seat·hr) are recorded. Scores are inter-rater averaged.

Few-shot scaffold (8 exemplars from the OCC tutorial set), self-repair loop with up to 3 OCC error feedbacks. Executes in a Vercel Sandbox per call.

Native BREP generator. Outputs valid AP242 STEP. Trained on the Zoo internal corpus + filtered GrabCAD. Endpoint: text-to-cad.zoo.dev/api.

Closed-beta natural-language modeller; emits parametric Onshape FeatureScript export. Tested through partner key (rate-limited 60 req/h).

Same scaffold as the Claude pipeline for fair comparison. Self-repair budget capped at 3 attempts.

Mesh-only output (OpenSCAD does not produce BREP); STEP round-trip therefore disabled. CSG kernel: CGAL.

Same prompt template as the Gemini pipeline. Output is mesh-only.

Transformer over CAD command sequences (extrude, revolve, sketch). Limited prompt vocabulary; we wrap with a Claude-3.5-mini paraphraser to convert natural prompts into the in-distribution token grammar.

Diffusion model over structured latents. Outputs a mesh only; STEP round-trip and BREP-fidelity tasks score 0 by definition.

Aimed at game/UX assets, not engineering CAD. Included as a non-CAD baseline to quantify the gap.