libassimp

Assimp for TypeScript and WebAssembly: import 69 3D formats and export 15 formats in browsers and Node.js.

| I want to… | Start here | | -------------------------------------- | ------------------------------------------------------------------- | | Convert one model | Quick start | | Export several formats from one import | Import once, export many | | Load sidecars over a network | Resolve sidecars asynchronously | | Build a dynamic converter UI | Static capabilities | | Maintain or release the package | Maintainer guide |

Install

pnpm add libassimp

Quick start

import { convert } from 'libassimp';
import { readFile, writeFile } from 'node:fs/promises';

const bytes = new Uint8Array(await readFile('model.obj'));
const { files } = await convert({ name: 'model.obj', bytes }, { to: 'glb' });
await writeFile(files[0].name, files[0].bytes);

Import once, export many

import { convertFormats } from 'libassimp';
import { readFile } from 'node:fs/promises';

const bytes = new Uint8Array(await readFile('model.fbx'));
const [glb, binaryStl, obj] = await convertFormats(
  { name: 'model.fbx', bytes },
  {
    targets: [
      { to: 'glb' },
      { to: 'stl', exportOptions: { binary: true } },
      { to: 'obj', exportOptions: { materials: false } },
    ],
  },
);

console.log(glb.format, binaryStl.format, obj.files[0].name);

The positional result tuple preserves target order and literal format types. The source is copied and parsed once; exports run sequentially and the call is atomic.

Resolve sidecars asynchronously

import { convert } from 'libassimp';

const response = await fetch('https://assets.example/model.gltf');
const bytes = new Uint8Array(await response.arrayBuffer());
const { files } = await convert(
  { name: 'model.gltf', bytes },
  {
    to: 'glb',
    resolve: async (name) => {
      const sidecar = await fetch(new URL(name, response.url));
      return sidecar.ok ? new Uint8Array(await sidecar.arrayBuffer()) : undefined;
    },
  },
);

The same artifact automatically suspends with JSPI when the host supports it and transparently replays from a per-call resolver cache otherwise. createAssimp still accepts only wasmUrl, wasmBinary, and onLog.

Static capabilities

assimpCapabilities, conversionEdges, and defaultPostProcess are generated from the pinned Assimp source and are available without loading Wasm. Public targets are canonical: binary/ASCII choices use exportOptions.binary, OBJ materials use exportOptions.materials, and glb/gltf always mean glTF 2.

The single libassimp entry reads all 69 compiled extensions and writes all 15 canonical formats through libassimp.wasm.

Compatibility

See the canonical compatibility matrix for hosts, package entries, JSPI acceleration, replay fallback, and Wasm feature floors.

Versioning and stability

The package is prerelease. Public names, defaults, and generated capability metadata are reviewed API; see breaking changes.

Security and provenance

Releases are built by GitHub Actions with npm provenance. Report vulnerabilities through the security policy.

Documentation

Read the documentation, contribution guide, or maintainer guide.

License

Apache-2.0. Part of the Tau ecosystem.