# cascade-core Reusable CAD modeling engine built on [OpenCascade](https://github.com/Open-Cascade-SAS/OCCT) WASM. Evaluate CAD code in a Web Worker and get triangle mesh data back — no GUI dependencies. This is the headless engine that powers [Cascade Studio](https://zalo.github.io/CascadeStudio/). Use it to embed parametric CAD modeling in any web application.

## Install ```bash npm install cascade-core ``` ## Quick Start ```javascript import { CascadeEngine } from 'cascade-core'; const engine = new CascadeEngine({ workerUrl: './cascade-worker.js' }); await engine.init(); const result = await engine.evaluate(` let box = Box(20, 20, 20); FilletEdges(box, 3, Edges(box).max([0,0,1]).indices()); `, { guiState: { 'Cache?': true } }); // result.meshData = { faces: [...], edges: [...] } // Render with Three.js, Babylon.js, or any WebGL framework ``` Copy `cascade-worker.js`, `cascadestudio.wasm`, and `fonts/` from `node_modules/cascade-core/dist/` to your static assets directory. ## Examples These are all built with the cascade-core standard library — [try them live](https://zalo.github.io/CascadeStudio/):

## API ### `new CascadeEngine({ workerUrl })` Create an engine instance. `workerUrl` is the path to the bundled worker file. ### `engine.init() → Promise` Load the worker and OpenCascade WASM. Resolves when ready. ### `engine.evaluate(code, options?) → Promise<{ meshData, sceneOptions }>` Evaluate CAD code and return triangulated mesh data. - `code` — JavaScript string using the standard library (Box, Sphere, Sketch, etc.) - `options.guiState` — slider/checkbox state object - `options.maxDeviation` — mesh resolution (default 0.1) - Returns `{ meshData: { faces, edges }, sceneOptions }` ### `engine.meshHistoryStep(index, maxDeviation?) → Promise` Triangulate a specific modeling history step. ### `engine.exportSTEP() → Promise` Export the current shape as STEP file text. ### `engine.on(event, handler)` / `engine.off(event, handler)` Listen for events: `log`, `error`, `Progress`, `resetWorking`, `modelHistory`, `addSlider`, `addButton`, `addCheckbox`, `addTextbox`, `addDropdown`, `saveFile`. ### `engine.isReady` / `engine.isWorking` Boolean status properties. ### `engine.dispose()` Terminate the worker and clean up. ## Standard Library The evaluated code has access to these functions: - **Primitives**: `Box`, `Sphere`, `Cylinder`, `Cone`, `Circle`, `Polygon`, `Text3D`, `BSpline`, `Wedge` - **Sketch**: `new Sketch([x,y], plane?).LineTo().Fillet().ArcTo().BSplineTo().End().Face()` - **Transforms**: `Translate`, `Rotate`, `Scale`, `Mirror` - **Booleans**: `Union`, `Difference`, `Intersection` - **Operations**: `Extrude`, `Revolve`, `Loft`, `Pipe`, `Offset`, `FilletEdges`, `ChamferEdges` - **Selectors**: `Edges(shape).ofType().parallel().max().min().indices()` - **Measurement**: `Volume`, `SurfaceArea`, `CenterOfMass` - **GUI**: `Slider`, `Checkbox` (values come from `guiState`) See the full TypeScript definitions in `types/StandardLibraryIntellisense.ts`. ## OpenSCAD ```javascript import { OpenSCADTranspiler } from 'cascade-core'; const transpiler = new OpenSCADTranspiler(); const jsCode = transpiler.transpile(` difference() { cube(20, center=true); sphere(r=12); } `); const result = await engine.evaluate(jsCode); ``` ## Credits - [opencascade.js](https://github.com/donalffons/opencascade.js) (CAD Kernel — OCCT 8.0.0 RC4 via Embind) - [opentype.js](https://github.com/opentypejs/opentype.js) (Font Parsing for Text3D) - [potpack](https://github.com/mapbox/potpack) (Texture Atlas Packing) ## License MIT