code: function randomAxis(v) {
      v = v || new three.Vector3();
  
      v.x = three.Math.randFloatSpread(2.0);
      v.y = three.Math.randFloatSpread(2.0);
      v.z = three.Math.randFloatSpread(2.0);
      v.normalize();
  
      return v;
    }
docs: Get a random axis for quaternion rotation.
  
  @param {THREE.Vector3=} v Option vector to store result in.
  @returns {THREE.Vector3}