Animation and deformation
Animation combines clip playback, skeletal deformation, and morph targets to bring characters and scene objects to life.
The RobotExpressive sample in the glTF Asset Studio demonstrates this capability. The embedded viewer opens that asset and retains the studio controls for exploring it.
API
The engine animation mixer underlies imported clip playback. The glTF adapter exposes it through scenegraphs.animator: selectClip() activates a source clip, crossFadeDuration is in seconds, and setTime() advances to absolute milliseconds. setGLTFMorphWeights() changes the weights of a mapped mesh node.
import {createScenegraphsFromGLTF, setGLTFMorphWeights} from '@luma.gl/gltf';
const scenegraphs = createScenegraphsFromGLTF(device, gltf);
scenegraphs.animator.selectClip('Walking');
scenegraphs.animator.selectClip('Running', {crossFadeDuration: 0.3});
scenegraphs.animator.setTime(1000);
// Node 13 is the face in the RobotExpressive sample.
const faceNode = scenegraphs.gltfNodeIndexToNodeMap.get(13);
if (faceNode) {
setGLTFMorphWeights(faceNode, [0.8, 0, 0]);
}
Clip names and node indices are asset-specific. Active morph animation may overwrite manually set weights on subsequent frames.
glTF support
Node translation, rotation, scale, skins, and morph-weight animation are core glTF features. KHR_animation_pointer additionally targets supported material, texture-transform, camera, light, and visibility properties. The animation reference describes playback and supported targets.
See glTF materials and textures, glTF animation, and the extension support matrix for adapter details and current support limits.