OpenCascade.jsModule shape
Top-level fields exposed on the resolved OCCT module — namespaces, runtime helpers, FS.
The object returned from init() carries every bound class plus emscripten
runtime helpers.
Bound classes and namespaces
Direct properties named after OCCT classes:
const oc = await init({ locateFile });
const box = new oc.BRepPrimAPI_MakeBox(10, 10, 10);
const point = new oc.gp_Pnt(0, 0, 0);OCCT namespaces (e.g. TopoDS, Interface_Static, XCAFDoc_DocumentTool)
appear as static-method-only objects:
oc.Interface_Static.SetIVal('write.step.schema', 5);
const edge = oc.TopoDS.Edge(genericShape);
const shapeTool = oc.XCAFDoc_DocumentTool.ShapeTool(doc.Main()).get();Filesystem (oc.FS)
The emscripten MEMFS bridge. Used to write OCCT output (STEP, GLB, IGES)
to an in-memory path, then read the bytes out.
const path = `/out_${Date.now()}.step`;
writer.Write(path);
const bytes = oc.FS.readFile(path) as Uint8Array;
oc.FS.unlink(path);| Method | Purpose |
|---|---|
FS.readFile(path) | Returns bytes as Uint8Array (view into wasm memory — copy out before unlink) |
FS.writeFile(path, bytes) | Write input file (e.g. for STEPControl_Reader.ReadFile) |
FS.unlink(path) | Free the MEMFS path |
FS.mkdir(path) | Create directory (rare — OCCT writes to / by default) |
FS.readdir(path) | List directory contents |
Full FS API: emscripten FS reference.
Heap views
| Property | Type |
|---|---|
oc.HEAP8 | Int8Array view of wasm memory |
oc.HEAPU8 | Uint8Array |
oc.HEAP16, HEAPU16 | 16-bit views |
oc.HEAP32, HEAPU32 | 32-bit views |
oc.HEAPF32, HEAPF64 | Float views |
Use for advanced interop (e.g. reading bytes at a Standard_Address pointer
returned from a low-level OCCT API). Most consumers never need these.
Exception helpers
import init, { getExceptionMessage } from '@taucad/opencascade.js';
// see /docs/package/guides/debugging-wasm-exceptionsModule re-init
Calling init() a second time re-instantiates the wasm module —
expensive, and creates two parallel C++ heaps that don't share state. Always
memoise behind a singleton; see init function.