three.js/examples/jsm/webxr/XRHandMeshModel.js

import { GLTFLoader } from '../loaders/GLTFLoader.js';

const DEFAULT_HAND_PROFILE_PATH = 'https://cdn.jsdelivr.net/npm/@webxr-input-profiles/assets@1.0/dist/profiles/generic-hand/';

class XRHandMeshModel {

	constructor( handModel, controller, path, handedness, loader = null, onLoad = null ) {

		this.controller = controller;
		this.handModel = handModel;

		this.bones = [];

		if ( loader === null ) {

			loader = new GLTFLoader();
			loader.setPath( path || DEFAULT_HAND_PROFILE_PATH );

		}

		loader.load( `${handedness}.glb`, gltf => {

			const object = gltf.scene.children[ 0 ];
			this.handModel.add( object );

			const mesh = object.getObjectByProperty( 'type', 'SkinnedMesh' );
			mesh.frustumCulled = false;
			mesh.castShadow = true;
			mesh.receiveShadow = true;

			const joints = [
				'wrist',
				'thumb-metacarpal',
				'thumb-phalanx-proximal',
				'thumb-phalanx-distal',
				'thumb-tip',
				'index-finger-metacarpal',
				'index-finger-phalanx-proximal',
				'index-finger-phalanx-intermediate',
				'index-finger-phalanx-distal',
				'index-finger-tip',
				'middle-finger-metacarpal',
				'middle-finger-phalanx-proximal',
				'middle-finger-phalanx-intermediate',
				'middle-finger-phalanx-distal',
				'middle-finger-tip',
				'ring-finger-metacarpal',
				'ring-finger-phalanx-proximal',
				'ring-finger-phalanx-intermediate',
				'ring-finger-phalanx-distal',
				'ring-finger-tip',
				'pinky-finger-metacarpal',
				'pinky-finger-phalanx-proximal',
				'pinky-finger-phalanx-intermediate',
				'pinky-finger-phalanx-distal',
				'pinky-finger-tip',
			];

			joints.forEach( jointName => {

				const bone = object.getObjectByName( jointName );

				if ( bone !== undefined ) {

					bone.jointName = jointName;

				} else {

					console.warn( `Couldn't find ${jointName} in ${handedness} hand mesh` );

				}

				this.bones.push( bone );

			} );

			if ( onLoad ) onLoad( object );

		} );

	}

	updateMesh() {

		// XR Joints
		const XRJoints = this.controller.joints;

		for ( let i = 0; i < this.bones.length; i ++ ) {

			const bone = this.bones[ i ];

			if ( bone ) {

				const XRJoint = XRJoints[ bone.jointName ];

				if ( XRJoint.visible ) {

					const position = XRJoint.position;

					bone.position.copy( position );
					bone.quaternion.copy( XRJoint.quaternion );
					// bone.scale.setScalar( XRJoint.jointRadius || defaultRadius );

				}

			}

		}

	}

}

export { XRHandMeshModel };