SynthCAD

SynthCAD is a small build123d CAD workflow for generating, inspecting, and exporting CAD parts from Python.

The synthcad/ package is the reusable framework: CLIs, registries, export helpers, inspection tools, web viewer assets, and generic CAD utilities. Project-owned CAD source, references, tests, docs, and target declarations live under projects/<project-slug>/.

Demo

Photos of the physical robot and printed chassis details:

Built flat disk robot	Printed chassis internals

Quick Start

uv run synthcad-build --project flat-disk-robot
uv run synthcad-build --target m3564c-six-axis-load-cell
uv run synthcad-probe --target flat-disk-robot --children
uv run synthcad-inspect --target flat-disk-robot
uv run show-interference --target flat-disk-robot
uv run synthcad-urdf --target flat-disk-robot

Generated STEP, STL, GLB, inspection, and URDF artifacts are written under each project's generated/ directory by default. Generated directories are intentionally ignored by git.

Build Targets

• flat-disk-robot-chassis: printable 216 mm chassis.
• flat-disk-robot-lid: printable service lid.
• flat-disk-robot: reference assembly with motors, wheels, electronics, sensors, battery, and lid.
• m3564c-six-axis-load-cell: reference model of the Sunrise Instruments M3564C 60 mm six-axis circular load cell.

The source references used by the flat disk robot live under projects/flat-disk-robot/real-parts/. BREP cache files may be generated beside STEP inputs during local builds; they are ignored and should not be committed. The M3564C source drawing lives under projects/m3564c-load-cell/real-parts/.

Each project declares its build and optional URDF targets in projects/<project-slug>/targets.py. uv run synthcad-build --list discovers those project-local declarations without keeping project factories in the core package.

GitHub CI

.github/workflows/synthcad-ci.yml selects affected projects from changed paths, runs root framework tests plus those projects' local tests, exports only the selected projects, and builds the PR diff viewer for selected targets. Core framework changes fan out to every project; project-local changes stay scoped to that project.

Example: PR #1 CAD review comment.

Agent Skills

This repository can be used with vercel-labs/skills:

npx skills add BenCaunt/SynthCAD --list
npx skills add BenCaunt/SynthCAD --skill synthcad-cad-authoring
npx skills add BenCaunt/SynthCAD --skill synthcad-setup-github-project

Skill sources are in skills/. The repo intentionally does not include a root SKILL.md, so skill installers copy only the selected skill directory instead of the whole CAD repository.

Validation

Run the regression suite:

uv run pytest

For geometry changes, regenerate exports and inspect the affected project before calling the change done:

PROJECT=flat-disk-robot
uv run synthcad-build --project "$PROJECT"
uv run synthcad-inspect --project "$PROJECT" --output-dir "projects/$PROJECT/generated/inspection"
uv run synthcad-report --project "$PROJECT"

See projects/flat-disk-robot/docs/flat-disk-robot-notes.md for robot-specific layout assumptions, and projects/m3564c-load-cell/docs/m3564c-load-cell-notes.md for the M3564C drawing interpretation.