BREP-004 · BREP Fidelity · difficulty 4/5

NURBS-handle goblet (G2 swept loft)

sha256:9bb19af0271ac46e…

§1Prompt verbatim

Goblet: cup is a swept-revolved NURBS surface (12 control points along generatrix), stem is a 10 mm chamfered cylinder, base is a Ø 70 × 5 mm disc. Cup-to-stem and stem-to-base junctions must be G2 continuous. Export AP242.

§2Ground-truth spec

shells1

watertighttrue

manifoldtrue

acceptance ε±0.05 mm

featuresg2_continuity_cup_stem, g2_continuity_stem_base

§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✓

Zoo Text-to-CAD

Zoo (KittyCAD)

0.76010✓

Human Baseline (Mech-E)

CAD-Coder Labs (research)

0.56912✗

Qwen3 Coder → CadQuery

Alibaba + CadQuery 2.4

0.56811✗

OpenAI o4 (reasoning) → CadQuery

OpenAI + CadQuery 2.4

0.56413✗

DeepCAD

Wu et al. 2021 (research)

0.52712✗

Claude Sonnet 4.6 → CadQuery

Anthropic + CadQuery 2.4

0.51913✗

DeepSeek R1 (reasoning) → CadQuery

DeepSeek + CadQuery 2.4

0.50513✗

Claude Opus 4.7 → CadQuery

Anthropic + CadQuery 2.4

0.5019✗

Gemini 2.5 Flash → CadQuery

Google + CadQuery 2.4

0.49111✗

Claude Haiku 4.5 → CadQuery

Anthropic + CadQuery 2.4

0.44715✗

GPT-5 → CadQuery

OpenAI + CadQuery 2.4

0.36715✗

GPT-5 Mini → OpenSCAD

OpenAI + OpenSCAD 2024.06

0.10943✗

Claude Opus 4.7 → OpenSCAD

Anthropic + OpenSCAD 2024.06

0.0900✗

Gemini 2.5 Pro → OpenSCAD

Google + OpenSCAD 2024.06

0.0710✗

Llama 3.3 70B → OpenSCAD

Meta + OpenSCAD 2024.06

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.	Euler-Poincaré Compliance	STEP RT	FeatRec	P@1	p50	latency	cost
Zoo Text-to-CAD	✓	0.963	✓	0.097	0.722	1.000	—	6.2s	$0.188
Human Baseline (Mech-E)	✓	0.970	✓	0.071	0.855	0.000	—	513.2s	$6.506
Adam (CADcrush)	✓	0.942	✓	0.119	0.707	0.000	—	10.8s	$0.322
CAD-Coder R1	✓	0.931	✓	0.118	0.642	0.000	—	6.2s	$0.005
Qwen3 Coder → CadQuery	✓	0.931	✓	0.109	0.615	0.000	—	21.6s	$0.030
OpenAI o4 (reasoning) → CadQuery	✓	0.933	✓	0.133	0.715	0.000	—	93.8s	$1.252
DeepCAD	✓	0.935	✓	0.121	0.498	0.000	—	4.4s	$0.021
Claude Sonnet 4.6 → CadQuery	✓	0.925	×	0.127	0.638	0.000	—	15.1s	$0.071
DeepSeek R1 (reasoning) → CadQuery	✓	0.925	×	0.131	0.595	0.000	—	91.9s	$0.043
Claude Opus 4.7 → CadQuery	✓	0.930	✓	0.094	0.773	0.000	—	38.0s	$0.372
Gemini 2.5 Flash → CadQuery	✓	0.929	✓	0.109	0.544	0.000	—	15.4s	$0.020
Claude Haiku 4.5 → CadQuery	✓	0.917	×	0.151	0.486	0.000	—	9.6s	$0.022
GPT-5 → CadQuery	×	0.907	×	0.150	0.639	0.000	—	29.4s	$0.206
GPT-5 Mini → OpenSCAD	×	0.867	×	0.428	0.450	0.000	—	17.3s	$0.009
Claude Opus 4.7 → OpenSCAD	×	0.863	×	—	0.526	0.000	—	28.8s	$0.291
Gemini 2.5 Pro → OpenSCAD	×	0.860	×	—	0.539	0.000	—	24.0s	$0.100
Llama 3.3 70B → OpenSCAD	×	0.860	×	0.708	0.399	0.000	—	27.6s	$0.019
Trellis 3D	×	0.850	×	—	0.215	0.000	—	15.6s	$0.049
Spline AI	×	0.850	×	—	0.086	0.000	—	8.4s	$0.037
Hunyuan3D-2	×	0.850	×	1.046	0.215	0.000	—	41.4s	$0.057