opencad

Agentic CAD pipeline

Parts and machines, modelled by agents and checked by OpenCascade.

Each design starts as a contract with a source for every number. A worker writes editable CAD on build123d, CadQuery, FreeCAD or Zoo; the exported STEP is measured independently against the contract; and every handoff ships a STEP and an STL you can print.

34designs
14machines
30passing all gates
68printable STLs
4CAD backends
Aleph compute stackFeatured: Aleph compute stackOpen the interactive review →

14 designs

Machines

Assemblies of placed parts on measured joints, with motion sweeps, clearances and, where declared, fluid regions and simulations.

Aleph compute stack iso view
MachinePASS 8/8

Aleph compute stack

Reference model of the Aleph base board, carrier board, Jetson Orin Nano module and heatsink-fan on M2.5 standoffs, for designing enclosures and mounts.

8 bodies4 part designsbuild123d
Open design review
Compound gear train iso view
MachinePASS 10/10

Compound gear train

Compound spur-gear train on a base plate, every gear on its own revolute joint.

4 bodies4 part designsbuild123dscored truth case
Open design review
Crank-slider iso view
MachinePASS 10/10

Crank-slider

Offset crank-slider mechanism of four separate solids in stacked layers, with a full-turn motion sweep.

4 bodies4 part designsbuild123dscored truth case
Open design review
Disc brake iso view
MachinePASS 13/13

Disc brake

Rebuild of the COMSOL heat-generation-in-a-disc-brake model with a thermal simulation.

2 bodies2 part designsbuild123dscored truth case
Open design review
FAN-01 axial fan iso view
MachineFAIL 11/12

FAN-01 axial fan

EAA benchmark low-pressure axial fan with a nine-blade rotor in its rig, with fluid regions and an MRF flow analysis.

6 bodiesbuild123dscored truth case
Open design review
Peristaltic pump iso view
MachinePASS 10/10

Peristaltic pump

The open-source 3D-printed peristaltic pump of Behrens et al., placed from its published STEP parts with a modelled silicone tube and a roller-pass motion check.

14 bodies1 part designsbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design review
Planetary gear set iso view
MachinePASS 10/10

Planetary gear set

Planetary set with a fixed ring, built as seven separate solids from five part designs.

7 bodies5 part designsbuild123dscored truth case
Open design review
Sprite iso view
MachinePASS 9/9

Sprite

Printable tail-sitter FPV drone. A sled on the carbon frame carries the Aleph compute stack and the battery; the shell and nose cover slide on over it.

31 bodies14 part designsbuild123d
Open design review

2 designs

Parts

Standalone printed parts designed from datasheets, drawings and photos.

3DBenchy iso view
PartPASS 11/11

3DBenchy

The standard tugboat calibration print, modelled from scratch.

60.0 × 31.0 × 48.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCL
Open design reviewSTL
Aleph stack case iso view
PartFAIL 10/11

Aleph stack case

Printed enclosure for the full Aleph stack, with the heatsink rising through the lid for airflow and openings for every connector.

99.7 × 65.4 × 37.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCL
Open design reviewSTL

18 designs

Reconstruction corpus

Parts rebuilt from public references and scored against held-back truth geometry.

Chiral key plate iso view
ReconstructionPASS 11/11

Chiral key plate

Square key plate built from a text specification.

80.0 × 80.0 × 8.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
Enclosure base iso view
ReconstructionPASS 11/11

Enclosure base

Lower body of a two-part box enclosure, 100 × 150 × 47 mm with rounded corners.

100.0 × 150.0 × 47.0 mmbuild123d, CadQuery, FreeCADscored truth case
Open design reviewSTL
Fusion 360 Gallery 01184 iso view
ReconstructionPASS 11/11

Fusion 360 Gallery 01184

Parametric reconstruction of a Fusion 360 Gallery body from its joint-set data.

10.0 × 88.0 × 50.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
NIST AM test artifact iso view
ReconstructionPASS 11/11

NIST AM test artifact

The NIST additive-manufacturing test artifact (Moylan et al. 2014) from its drawing and paper.

141.4 × 141.4 × 17.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
NIST AMB2022-01 bridge iso view
ReconstructionPASS 11/11

NIST AMB2022-01 bridge

The NIST AM-Bench 2022 individual bridge artifact from its description and figures.

75.0 × 5.0 × 12.5 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
Prusa MINI extruder front iso view
ReconstructionPASS 11/11

Prusa MINI extruder front

The Original Prusa MINI extruder front housing from renders and section drawings.

53.0 × 14.0 × 63.7 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
Raspberry Pi 5 enclosure iso view
ReconstructionPASS 11/11

Raspberry Pi 5 enclosure

Two-piece FFF-printed enclosure, base and removable lid, for a Raspberry Pi 5.

102.0 × 73.0 × 33.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL
Spur gear pair iso view
ReconstructionPASS 11/11

Spur gear pair

Module 2, 20° pressure-angle spur-gear pair and carrier plate to an exact specification.

126.9 × 83.8 × 13.0 mmbuild123d, CadQuery, FreeCAD, Zoo KCLscored truth case
Open design reviewSTL

3 published comparisons

Bake-off

The same contract authored by the same agent on all four CAD backends, with every turn's tokens, dollars and time metered. Latest: 3DBenchy, 2026-10-17.

Open the bake-off log

How it works

From intent to a printable handoff

Python is the control plane. Agents do the modelling and spatial reasoning; every claim they make is re-measured on the exported geometry.

01 · Contract

Design

Sources (datasheets, drawings, photos, reference meshes) become one contract.yaml or assembly.yaml with provenance on every parameter.

02 · Model

Build

A worker plans the construction and writes parametric source on the chosen backend; a blockout checks scale and frame first.

03 · Gates

Verify

OpenCascade reads the STEP for envelope, mass properties, features, edits and export agreement: 12 gates per part, 14 per machine.

04 · Handoff

Print

The handoff is the gated STEP, an STL in millimetres, a GLB for the viewer, and the provenance that binds them to the source.

Evidence

Claims, verdicts and geometry

ok: true in a stage file is the worker's claim. gate_feedback.json is the verdict, and the exported STEP is authoritative.

A failing design stays listed with its failing gates. A PASS means the geometry agrees with its contract within tolerance; it is not a physical test of the printed part.