Preprint · cad-bench/v0.5 · sweep 2026-04-12open · MIT
CAD·Benchv0.5
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ASM-005 · Assembly & Mating · difficulty 3/5

Pin-in-hole, H7/g6 sliding fit

sha256:5cd0a7e3b4f10918

§1Prompt verbatim

Cylindrical pin Ø 10 g6 × 40 mm long, chamfered 1×45° on both ends. Held-out partner has a Ø 10 H7 through-hole; the assembled clearance must lie in [0.005, 0.029] mm.

§2Ground-truth spec

shells1
watertighttrue
manifoldtrue
acceptance ε±0.005 mm
clearance[0.005, 0.029] mm

§3Reference render

canonical reference · drag to orbit, scroll to zoom

Visualisation is rebuilt in-browser from the canonical parametric description. Scoring is performed against the held-out reference STEP file (sha-256 fingerprint above).

§4Per-agent renders

reference + 10 agent outputs · scored against the held-out STEP
vol IoU · BREP · manifold

Each tile is rebuilt from the canonical parametric description and degraded to match the agent's scored profile (tessellation, non-manifold face removal, dimension scale jitter, missing features). Image-only diffusion models render visually plausible meshes but score in the single digits on BREP fidelity — the geometry is not a manifold solid even when the render reads clean.

§5Per-agent metrics

ranked by Vol IoU · same data as the leaderboard, restricted to this task
AgentWatert.Manif.FeatRecMating ClearanceFit-Class ComplianceP@1p50latencycost
Human Baseline (Mech-E)0.9790.9390.8020.8491.000805.3s$5.119
Zoo Text-to-CAD0.9400.7130.7710.5730.0007.2s$0.166
Claude Opus 4.7 → CadQuery0.9470.7770.6010.4140.00040.3s$0.296
GPT-5 → CadQuery0.9360.6930.5770.3760.00036.2s$0.179
Adam (CADcrush)0.9340.7010.5930.4460.0007.9s$0.263
Claude Opus 4.7 → OpenSCAD×0.9100.6090.4990.2250.00036.8s$0.318
DeepCAD×0.9010.4290.4420.1730.0005.3s$0.021
Gemini 2.5 Pro → OpenSCAD×0.9030.5460.4610.2290.00027.2s$0.104
Trellis 3D×0.8500.1890.0960.0050.0009.1s$0.051
Spline AI×0.8500.0850.0490.0010.0009.8s$0.032