Visualize shape helper

Every example in this docs site can inline the XCAF → mesh → GLB → blob URL pipeline. This page documents the canonical helper so you can import it once instead of copying the boilerplate into every script.

`visualizeDoc`

Build a GLB blob URL from an XCAF document that already contains tessellated shapes:

lib/visualize.ts

import type { OpenCascadeInstance } from '@taucad/opencascade.js';

export const visualizeDoc = async (
  oc: OpenCascadeInstance,
  doc: InstanceType<OpenCascadeInstance['TDocStd_Document']>,
): Promise<string> => {
  using writer = new oc.RWGltf_CafWriter(new oc.TCollection_AsciiString_2('out.glb'), true);
  writer.Perform(doc, new oc.TColStd_IndexedDataMapOfStringString(), new oc.Message_ProgressRange());

  const fileName = 'out.glb';
  const buffer = oc.FS.readFile(fileName, { encoding: 'binary' });
  oc.FS.unlink(fileName);

  const blob = new Blob([buffer], { type: 'model/gltf-binary' });
  return URL.createObjectURL(blob);
};

`visualizeShapes`

Convenience wrapper — accepts one or more TopoDS_Shape values, builds the XCAF document, meshes, and returns a GLB blob URL:

lib/visualize.ts

import type { OpenCascadeInstance, TopoDS_Shape } from '@taucad/opencascade.js';

export const visualizeShapes = async (
  oc: OpenCascadeInstance,
  ...shapes: TopoDS_Shape[]
): Promise<string> => {
  using doc = new oc.TDocStd_Document(new oc.TCollection_ExtendedString_1());
  const shapeTool = oc.XCAFDoc_DocumentTool.ShapeTool(doc.Main()).get();

  for (const shape of shapes) {
    using mesh = new oc.BRepMesh_IncrementalMesh(shape, 0.1, false, 0.1, false);
    const newShape = shapeTool.NewShape();
    shapeTool.SetShape(newShape, shape);
  }

  return visualizeDoc(oc, doc);
};

When to inline vs import

First read: keep the pipeline inline in tutorials so every step is visible.
Production code: import from a single lib/visualize.ts module.
Multi-material assemblies: build the XCAF document yourself (see Boolean logo for per-subset PBR assignment).

visualizeDoc

visualizeShapes

When to inline vs import

On this page

`visualizeDoc`

`visualizeShapes`