Human Baseline (Mech-E)
A · Engineering-Capablecomposite 85.7 [82.2, 88.3]p5 46.6IRT θ 99.9
n=4 senior engineers· vOnshape-2026-04· released 2026-04-01· Human· emits BREP· open
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.
solid: agent · dashed: human baseline
PER-CATEGORY SCORE (95 % CI)
Geometric Primitives
92.9
Boolean Robustness
74.2
BREP Fidelity
95.9
Free-form Surfaces
92.1
Parametric Mechanical Parts
88.0
Assembly & Mating
84.2
Standards Compliance
85.4
Sheet-Metal Bodies
84.5
Sealing-Groove Design
90.8
Kinematic Mechanisms
89.7
DFM · 3-Axis CNC
87.0
DFM · Injection Mould
82.7
DFM · FDM 3D Print
85.8
CAM Toolpath Validity
84.9
Constraint Solving & Editability
86.6
Reverse Engineering
55.2
2-D Sketch Constraints
87.3
Functional Intent · FEA-Gated
85.5
Paraphrase Robustness
97.1
Confidence Calibration
46.5
MEAN METRICS BY LAYER
L1 · Geometry
| Category | Vol IoU | Chamfer | Hausdorff | NormCons | Watert. | Manif. | Euler | STEP RT | P@1 |
|---|---|---|---|---|---|---|---|---|---|
| Geometric Primitives | 0.803 | 0.122 | — | — | — | 0.973 | — | — | — |
| Boolean Robustness | 0.598 | — | — | — | — | 0.770 | — | — | — |
| BREP Fidelity | — | — | — | — | — | 0.968 | — | 0.073 | — |
| Free-form Surfaces | — | 0.134 | 0.644 | 0.907 | — | — | — | — | — |
L2 · Engineering
| Category | Dim RMSE | GD&T | FeatRec | Mating | Fit-Cls | Std |
|---|---|---|---|---|---|---|
| Parametric Mechanical Parts | 0.108 | 0.837 | 0.911 | — | — | — |
| Assembly & Mating | — | — | 0.860 | 0.840 | 0.827 | — |
| Standards Compliance | — | 0.837 | — | — | — | 0.871 |
| Sheet-Metal Bodies | 0.107 | — | 0.845 | — | — | — |
| Sealing-Groove Design | 0.097 | — | — | — | — | 0.913 |
| Kinematic Mechanisms | — | — | 0.928 | 0.877 | — | — |
L3 · Manufacturing
| Category | DFM | Draft | Min-Wall | CAM-Reach | Supp | Wall-Unif |
|---|---|---|---|---|---|---|
| DFM · 3-Axis CNC | 92.350 | — | 0.860 | 0.826 | — | — |
| DFM · Injection Mould | — | 0.828 | 0.778 | — | — | 0.873 |
| DFM · FDM 3D Print | 90.467 | — | 0.820 | — | 0.305 | — |
| CAM Toolpath Validity | — | — | — | 0.821 | — | — |
L4 · Cognition
| Category | ParamEdit | ConSolve | P-Range | FEA-σ | Para σ | Seed σ | Brier | EditLat |
|---|---|---|---|---|---|---|---|---|
| Constraint Solving & Editability | 0.872 | 0.871 | 0.856 | — | — | — | — | — |
| Reverse Engineering | — | — | — | — | — | — | — | — |
| 2-D Sketch Constraints | — | 0.804 | — | — | — | — | — | — |
| Functional Intent · FEA-Gated | — | — | — | 0.795 | — | — | — | — |
| Paraphrase Robustness | — | — | — | — | 0.006 | 0.005 | — | — |
| Confidence Calibration | — | — | — | — | — | — | 0.035 | — |
TASK-BY-TASK ARTIFACTS
PRIM-001Hollow cylinder (60 × 40 × 100)0.8641.00PRIM-007Right hexagonal prism with pitch fillet0.9451.00BOOL-003Coplanar-face union (knife-edge stress)0.0000.00BOOL-009High-genus subtraction (lattice block)0.6560.00BREP-004NURBS-handle goblet (G2 swept loft)0.7400.00SURF-002Compressor blade (NACA 65-(12)10)0.6300.00MECH-014L-bracket with M6 + slotted hole0.7631.00MECH-022Stepped shaft with retaining-ring groove0.6900.00MECH-027Planetary-gear carrier plate0.6410.00ASM-005Pin-in-hole, H7/g6 sliding fit0.7661.00ASM-011Dovetail slide (60° flanks)0.6890.00STD-002ISO 4762 M8×30 socket-head cap screw0.7220.00SHEET-003U-channel bracket, 1.5 mm Al, k=0.400.8481.00SEAL-001AS568-214 face-seal groove0.8321.00KIN-002Four-bar linkage, Grashof crank-rocker0.6760.00DFMCNC-0023-ax-machinable manifold block0.8341.00DFMMOLD-002Injection-mouldable enclosure half0.7050.00DFMFDM-008FDM-printable hinge (no support)0.6920.00CAM-0015-pocket plate, Ø3 endmill finish0.8481.00PARAM-006Editable flange (bolt circle param sweep)0.8851.00PARAM-013Editable bracket (length+30 %, hole→M8)0.7180.00REVENG-002Three-view ortho → bracket0.6540.00REVENG-009Three-view ortho → housing with cores0.7370.00SKETCH-003Tangent-arc transition profile0.8611.00FUNC-001Cantilever bracket — 250 N tip load, 6061-T6, SF≥40.6520.00FUNC-007Heat-sink fin array for 25 W TO-2200.6330.00PARA-0015× paraphrased L-bracket0.7541.00CAL-003Confidence-calibrated planetary carrier0.5990.00PRIM-002Sphere with planar cap0.7750.00PRIM-003Right truncated cone (frustum)0.8020.00PRIM-004Square-base pyramid frustum0.8130.00PRIM-005Tilted-axis box (30°)0.6290.00PRIM-009Hollow torus (Ø100 mean × Ø8 tube, 1 mm wall)0.7930.00BOOL-001Tangent cylinder onto cube (line-of-contact)0.8101.00BOOL-002Two interpenetrating spheres (lens intersection)0.7290.00BOOL-005ε-offset extrusion (sliver-face stress)0.7951.00BREP-001Periodic-spline cylinder (closed in U)0.8351.00BREP-002G1-only loft (tangent discontinuity)0.6910.00BREP-007Trimmed sphere with hole through pole0.8201.00SURF-001Ergonomic mug handle (revolved spline)0.8261.00SURF-007Mouse top-shell (Class-A)0.7441.00MECH-002Bearing block — two 6204 deep-groove bearings0.5820.00MECH-005Cam-follower lever (eccentric pivot)0.8461.00MECH-018Heat-set insert boss array (4× M3)0.8211.00MECH-031Threaded cap with diamond knurl0.7400.00ASM-001Threaded coupling M16×1.5 (male+female pair)0.7701.00ASM-008Spline shaft + hub (DIN 5480 W25×1.25×18)0.7210.00ASM-013Bayonet quarter-turn mount0.8481.00STD-001ISO 7050 self-tapping screw ST4.2 × 160.8581.00STD-005ISO 8734 dowel pin Ø6 m6 × 300.7591.00STD-008ASME B18.6.3 button-head 1/4-20 × 5/80.7470.00SHEET-001Box-pan with corner relief cuts0.7831.00SHEET-0073-bend electronics chassis0.7250.00SEAL-004AS568-218 piston-type radial groove0.8101.00SEAL-007ISO 3601-2 quad-ring face groove0.8181.00KIN-005Geneva drive — 4 station0.6200.00KIN-008Planetary gearset full mesh (sun + 3 planets + ring)0.8051.00DFMCNC-0054-pocket plate, R 0.5 internal corners0.7340.00DFMCNC-009Long-aspect bracket (vise-fixturable)0.8671.00DFMCNC-0135-axis-only fish-mouth saddle0.7781.00DFMMOLD-005Telephone handset shell0.6370.00DFMFDM-002Bridge-test calibration cube0.7521.00DFMFDM-011Print-in-place hinge0.7541.00CAM-005T-slot pocket array (Ø 8 + Ø 4 endmills)0.6900.00PARAM-009Configurable bottle (height + cap params)0.7400.00REVENG-005ABC dataset stepped pulley (multi-view)0.0000.00SKETCH-014Symmetric four-bar profile0.8891.00FUNC-003Heat-sink for 60 W CoB LED0.6740.00PARA-0055× paraphrased planetary carrier0.7210.00CAL-007Confidence-bracketed mounting flange0.6940.00