code: function Intersector () {
    this.arrowHelper = this.createArrowHelper();
    this.raycaster = new THREE.Raycaster(new THREE.Vector3(), new THREE.Vector3(), 0, 0.2);
  }
docs: Helper for raycasting, which chooses a raycaster direction based on hand position. Also supports
  a debugging mode, in which the ray is visible.