FUNC-001 · Functional Intent · FEA-Gated · difficulty 5/5

Cantilever bracket — 250 N tip load, 6061-T6, SF≥4

sha256:33a91efbac0c1110…

§1Prompt verbatim

Design a cantilever bracket that bolts to a wall via two M6 holes 50 mm apart and supports a 250 N transverse tip load 80 mm from the wall, in 6061-T6 aluminium, with a static safety factor ≥ 4 against yield (σ_y = 276 MPa). Mass should be ≤ 60 g. Output STEP.

§2Ground-truth spec

shells1

watertighttrue

manifoldtrue

acceptance ε±0.1 mm

featuresM6_clearance_x2, load_pad

§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✓

Human Baseline (Mech-E)

Claude Opus 4.7 → CadQuery

Anthropic + CadQuery 2.4

OpenAI + CadQuery 2.4

0.30518✗

Gemini 2.5 Pro → OpenSCAD

Google + OpenSCAD 2024.06

0.1820✗

Claude Opus 4.7 → OpenSCAD

Anthropic + OpenSCAD 2024.06

0.1740✗

DeepCAD

Wu et al. 2021 (research)

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.	FeatRec	Min-Wall Compliance	FEA-Yield Pass	p50	latency	cost
Human Baseline (Mech-E)	✓	0.949	0.869	0.794	0.822	—	874.9s	$5.292
Zoo Text-to-CAD	✓	0.918	0.702	0.684	0.486	—	4.5s	$0.172
Claude Opus 4.7 → CadQuery	×	0.905	0.700	0.630	0.531	—	44.4s	$0.288
Adam (CADcrush)	×	0.905	0.635	0.644	0.404	—	12.1s	$0.281
GPT-5 → CadQuery	×	0.897	0.727	0.650	0.500	—	29.1s	$0.198
Gemini 2.5 Pro → OpenSCAD	×	0.876	0.468	0.546	0.370	—	20.9s	$0.100
Claude Opus 4.7 → OpenSCAD	×	0.878	0.583	0.602	0.408	—	40.0s	$0.297
DeepCAD	×	0.877	0.498	0.385	0.179	—	5.7s	$0.017
Trellis 3D	×	0.850	0.215	0.210	0.086	—	12.4s	$0.051
Spline AI	×	0.850	0.093	0.104	0.046	—	10.1s	$0.033