partforge

Turn a declarative part definition into a full parametric-CAD web app — a 3-D viewer, a control panel, geometry workers, and STL / STEP / 3MF export. You write one script (geometry build functions + a parameter schema); partforge renders the app.

Two geometry backends run in Web Workers: Manifold for fast preview meshes + STL/3MF, and Replicad (OpenCASCADE-in-WebAssembly) for exact STEP export. The viewer is three.js.

Requires a Vite-based app. partforge is published as plain ESM source and relies on Vite's worker / WASM / CSS import handling.

Install

npm install partforge

Use

// app.js
import { mount } from "partforge";
import part from "./parts/my-part.js";
mount(part, {
  createWorker: (name) =>
    new Worker(new URL("./part-worker.js", import.meta.url), { type: "module", name }),
});

// part-worker.js
import { runWorker } from "partforge/worker";
import part from "./parts/my-part.js";
runWorker(part);

Test your parts headlessly with partforge/testing (createManifoldKernel, handle, assemblyOverlaps, bootOcctKernel, meshVolume, bboxSize).

Smoke-test that an app actually boots (real Chromium, real worker/WASM): npm run check (or node scripts/check-app.mjs <entry>.html) — it loads the app and verifies the kernel boots with no errors. Needs Playwright: npm i -D playwright && npx playwright install chromium.

Authoring guide

docs/AUTHORING-PARTS.md is the full guide — the part contract, the geometry kernel API, the parameter schema, app wiring, testing, and gotchas. See Designing the control panel in that guide for how to write descriptions, hide internal params, and keep the interface simple while staying deeply adjustable. src/parts/demo.js is a minimal worked example; run npm run dev and open /demo.html to see it live.

• Agent clarification (request-a-pick): an external tool can ask the user to click geometry and get the Selection back — serve with ?pickserver, drive with partforge pick-serve + partforge pick "<prompt>" …. See skills/partforge/SKILL.md and the authoring guide.

License

MIT