Configuration-preserving AR handoff

BindingBuilder and ModelViewer can prepare the edited scene for Apple Quick Look and open that configuration in a phone’s web viewer. ModelViewer and BindingBuilder require a valid license.

In the standalone editor

Load a model, then click AR handoff in the preview’s upper-left tools. Preparation starts automatically. The QR code appears as soon as its phone link is ready, while USDZ conversion can continue in the background. The dialog also offers Download USDZ when that file is ready. The preview’s Download menu also opens this dialog. On iPhone/iPad, View in AR opens the prepared USDZ in Quick Look; launching remains a separate user gesture.

Changing configuration invalidates the prepared result. While the dialog is open, it automatically updates for those edits; when closed, it waits until opened again. Completed results are reused when reopening without edits. Failed preparation does not retry in a loop; choose Try again to retry. Live animation frames and direct scene mutations do not invalidate it automatically. For a captured skin/morph pose, pause at the desired pose and choose Refresh AR. Generated object URLs are released when the configuration changes, the feature is disabled, or the viewer unmounts.

Locally uploaded models can be exported to USDZ without uploading them anywhere. Transfer the downloaded file to an Apple device for Quick Look. A phone link needs durable model/environment URLs and a page reachable from the phone; localhost is rejected. Uploading a model in this editor does not make its browser Blob URL accessible on another device.

Enable it in ModelViewer


import { ModelViewer } from "@liveroom-tech/react-immersive";
import "@liveroom-tech/react-immersive/styles.css";
 
export function ConfiguredARViewer() {
  return (
    <ModelViewer
      licenseKey="your_license_key"
      modelUrl="https://assets.example.com/chair.glb"
      objectBindings="auto"
      xr={{ enabled: true, arHandoff: true, scaleMode: "real-world" }}
    />
  );
}

The flat equivalent is enableXR arHandoff. Existing WebXR AR/VR continues to present the live scene. Without arHandoff, the existing usdzUrl and plain phone QR behavior remains available. With it enabled, a supplied static usdzUrl is not used as a fallback for failed snapshot generation, because it could omit edits.

mobileHandoffUrl can point to a separate mobile page. That page must mount ModelViewer with arHandoff enabled, or the standalone BindingBuilder. The editor recognizes an incoming AR hash and opens the configured viewer directly.

Phone links restore full bindings, model instances, placements, active variants, scene settings, isolation and AR scale. They use a compressed ri-ar hash, eliding unchanged scene defaults. Restored state is owned by the receiving viewer and remains editable; host callbacks still run. Removing the hash or changing the host’s primary source exits restored state. Set autoRestore: false to read the link with readARHandoffUrl and apply it through your own controlled state.

Application adapters

ARHandoffOptions is accepted by arHandoff or xr.arHandoff. The standalone BindingBuilder also accepts arHandoff (default true) and mobileHandoffUrl.

Option	Behavior
`assetVersion?: string`	Change when replacing an asset at the same URL or mutating the scene directly; invalidates prepared results.
`maxTextureSize?: number`	Longest exported texture edge; integer 256–4096, default 2048.
`storage?: ViewerStateStorage`	Application-owned save/load for larger configurations. Install the same adapter on the receiving page.
`autoRestore?: boolean`	Read incoming AR hashes, default `true`.
`createUSDZ?: (request: ARHandoffRequest) => Promise<Blob \| string>`	Return a USDZ Blob or HTTP(S) asset URL from your conversion/cache service.
`createMobileUrl?: (request: ARHandoffRequest) => Promise<string>`	Return a reachable HTTP(S) viewer URL that restores this configuration, including any uploaded assets.
`onStatusChange?: (status: ARHandoffStatus) => void`	Reports `idle`, `preparing`, `ready`, `error` or `stale`. Ready means at least one handoff path is available.
`onError?: (error: Error) => void`	Reports preparation failures. USDZ and phone-link errors are shown independently.

Each request contains a detached state, a configurationKey, an abort signal, and exportUSDZ(): Promise<ARSnapshot>. The key is an opaque cache key and may contain configuration data; do not expose it as a public URL. The export function captures the currently loaded scene and is memoized within that request. Adapters should honor cancellation. App-owned remote URLs remain the application’s responsibility; the SDK only revokes Blob URLs it creates.

Built-in phone links embed local binding images as data URLs. Larger payloads require storage; no backend endpoint is supplied by the SDK. Stored IDs use ri-ar-id. Both inline and stored payloads are validated using the versioned viewer-state format. A QR URL is limited to 2200 characters, and viewer state to 5 MiB. Do not put secrets in binding metadata: a handoff shares that metadata.

Export and link utilities

The main and /utils entries export:

exportConfiguredUSDZ(sources, options): Promise<ARSnapshot>
createARHandoffUrl(state, baseUrl, storage?, signal?): Promise<string>
readARHandoffUrl(url, storage?, signal?): Promise<ShareableViewerState | null>

ARSnapshotSource provides scene: Object3D, optional instanceId, objectBindings, materialOverrides keyed by binding/model object IDs, and sceneConfig containing authored animation and sequence settings. Pass current rendered scenes/materials, not an unedited loader cache. The snapshot clones its resources and leaves source geometry and materials alive. ARExportOptions provides scaleMode, maxTextureSize, and signal. ARSnapshot returns blob, meshCount, triangleCount, scale, and warnings. Utilities that encode/decode JSON can run without React; textured USDZ export requires browser canvas/WebGL support. Resolve source asset URLs against their original page before passing a different mobile page as baseUrl.

What USDZ preserves

Visible triangle meshes, node/asset world transforms, PBR material overrides, textures, selected material variants, projected image/text decals, multi-material geometry groups, instanced meshes, mirrored geometry, double-sided faces, and the current skinned/morph pose are included. The group is centered horizontally and rests on Y=0. Normalized scale fits its longest visible dimension to one metre; real-world scale keeps one scene unit per metre.

Authored autoplay clips and the first autoplay sequence export object and skeletal motion into USDZ at 30 frames per second. Skeletal exports retain the bind geometry, joint hierarchy and vertex weights, with shared skeletons for material submeshes. Native clip speed and loop mode determine the sampled cycle. Multiple clips are baked into one timeline; Quick Look controls playback rather than the browser’s animation controls. The exported asset explicitly enables autoplay. Morph-target animation remains at the captured pose and produces an export warning. Use createUSDZ with an application converter when morph animation is required. Standalone exportConfiguredUSDZ callers supply the authored sceneConfig on each ARSnapshotSource to include animation.

WebXR presents the live scene, including skeletal/morph clips and sequence object, material and visibility tracks. Sequence camera tracks are skipped during AR so they do not override the phone’s tracked camera.

The WebXR overlay offers an animation selector and play/pause button when clips or sequences are available. Choosing an animation starts it; pause/resume retains its position, and playing a finished clip starts it again. Clips are grouped by visible model, with authored display names and hidden clips respected. Changing the selection stops the previous playback, including any active sequence, to avoid competing transforms. These controls belong to the WebXR DOM overlay; Apple Quick Look uses its own native interface and cannot display this toolbar. On the iPhone/iPad handoff page, choose a clip or sequence in the animation selector before tapping Start AR. Changing the selection prepares a new USDZ; the AR launch waits until it is ready. Project autoplay uses the saved settings. Choosing a phone animation does not change the saved project. To choose a different clip after launching Quick Look, return to the page, choose it and start AR again.

Viewer lighting, backgrounds, post-processing, annotations, measurement overlays and browser UI stay in the web viewer. USDZ also omits sequence camera, visibility and appearance tracks. Phone links restore authored configuration; temporary viewport tools such as exploded view are not serialized. Rendering can differ between the browser and Quick Look, especially advanced PBR effects and texture transforms. Export uses Three.js’s USDZExporter with its Quick Look compatibility mode.

Pending variants/merged models and unloaded textures produce a retryable error. Matcap, UV-checker, wireframe, vertex colors and unsupported materials require switching to supported PBR rendering or supplying createUSDZ. Streaming tiles need an application converter because only resident tiles are present locally. Cross-origin textures must permit canvas export. Real Quick Look appearance must be verified on the target Apple devices.