MECH-027 · Parametric Mechanical Parts · difficulty 5/5

Planetary-gear carrier plate

sha256:2b97cc4d1ef0aa55…

§1Prompt verbatim

Disc Ø 80 mm × 8 mm with: (a) central Ø 12 H7 bore, (b) 3 satellite bores Ø 6 H7 on a 30 mm PCD at 0/120/240°, (c) 6 M3 tapped holes on a 60 mm PCD at 30° offset, depth 6 mm, ISO 261 thread. True-position 0.05 mm to datum A (central bore axis).

§2Ground-truth spec

shells1

watertighttrue

manifoldtrue

acceptance ε±0.05 mm

featuresbore_H7_12, bore_H7_6_x3, thread_M3x6_x6, PCD_30, PCD_60

§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

canonical reference

REFERENCE

canonical · ground truth

1.000100✓

Claude Sonnet 4.6 → CadQuery

Anthropic + CadQuery 2.4

0.6608✗

Human Baseline (Mech-E)

n=4 senior engineers

0.6419✗

OpenAI o4 (reasoning) → CadQuery

OpenAI + CadQuery 2.4

0.60510✗

Claude Opus 4.7 → CadQuery

Anthropic + CadQuery 2.4

Claude Opus 4.7 → OpenSCAD

Anthropic + OpenSCAD 2024.06

0.5580✗

CAD-Coder R1

CAD-Coder Labs (research)

OpenAI + CadQuery 2.4

0.49010✗

Qwen3 Coder → CadQuery

Alibaba + CadQuery 2.4

0.49010✗

Gemini 2.5 Flash → CadQuery

Google + CadQuery 2.4

0.42815✗

GPT-5 Mini → OpenSCAD

OpenAI + OpenSCAD 2024.06

0.38017✗

Gemini 2.5 Pro → OpenSCAD

Google + OpenSCAD 2024.06

0.3670✗

Claude Haiku 4.5 → CadQuery

Anthropic + CadQuery 2.4

0.24324✗

DeepCAD

Wu et al. 2021 (research)

0.21722✗

Llama 3.3 70B → OpenSCAD

Meta + OpenSCAD 2024.06

no manifold solid produced

no manifold solid produced

DeepSeek R1 (reasoning) → CadQuery

DeepSeek + CadQuery 2.4

—61✗

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

Agent	Watert.	Manif.	Named-Dimension RMSE	GD&T Compliance	FeatRec	p50	latency	cost
Claude Sonnet 4.6 → CadQuery	✓	0.949	0.193	0.553	0.722	—	18.1s	$0.064
Human Baseline (Mech-E)	✓	0.948	0.072	0.827	0.915	—	675.1s	$6.019
OpenAI o4 (reasoning) → CadQuery	✓	0.941	0.175	0.706	0.722	—	120.7s	$1.086
Claude Opus 4.7 → CadQuery	✓	0.944	0.174	0.664	0.754	—	42.8s	$0.381
Adam (CADcrush)	✓	0.935	0.178	0.696	0.668	—	9.5s	$0.244
Claude Opus 4.7 → OpenSCAD	✓	0.930	0.238	0.476	0.591	—	22.9s	$0.342
CAD-Coder R1	✓	0.926	0.255	0.473	0.657	—	4.6s	$0.006
Zoo Text-to-CAD	✓	0.933	0.222	0.677	0.750	—	4.6s	$0.163
GPT-5 → CadQuery	✓	0.928	0.242	0.549	0.660	—	52.6s	$0.182
Qwen3 Coder → CadQuery	✓	0.927	0.292	0.413	0.646	—	13.3s	$0.032
Gemini 2.5 Flash → CadQuery	✓	0.914	0.304	0.489	0.538	—	11.7s	$0.022
GPT-5 Mini → OpenSCAD	×	0.903	0.307	0.285	0.447	—	15.4s	$0.011
Gemini 2.5 Pro → OpenSCAD	×	0.906	0.236	0.400	0.469	—	24.7s	$0.083
Claude Haiku 4.5 → CadQuery	×	0.885	0.291	0.384	0.500	—	9.3s	$0.022
DeepCAD	×	0.882	0.325	0.362	0.457	—	4.2s	$0.022
Llama 3.3 70B → OpenSCAD	×	0.880	0.397	0.294	0.445	—	21.4s	$0.023
Hunyuan3D-2	×	0.862	0.516	0.057	0.220	—	35.9s	$0.069
Trellis 3D kernel error: BRepCheck_NotClosed	×	0.000	—	—	—	—	11.0s	$0.050
Spline AI	×	0.850	0.546	0.029	0.088	—	7.0s	$0.036
DeepSeek R1 (reasoning) → CadQuery kernel error: BRepCheck_NotClosed	×	0.000	—	—	—	—	88.5s	$0.038