constructor( controller ) {

		super();

		/**
		 * The hand controller.
		 *
		 * @type {Group}
		 */
		this.controller = controller;

		/**
		 * The motion controller.
		 *
		 * @type {?MotionController}
		 * @default null
		 */
		this.motionController = null;

		/**
		 * The controller's environment map.
		 *
		 * @type {?Texture}
		 * @default null
		 */
		this.envMap = null;

		/**
		 * The model mesh.
		 *
		 * @type {Mesh}
		 * @default null
		 */
		this.mesh = null;

	}
Constructs a new XR hand model.

@param {Group} controller - The hand controller.