Vector3 rotated3(Vector3 arg, [ Vector3 out ])

Rotate a copy of arg of type Vector3 using the rotation defined by this. If a out parameter is supplied, the copy is stored in out.

Source 

Vector3 rotated3(Vector3 arg, [Vector3 out]) {
  if (out == null) {
    out = new Vector3.copy(arg);
  } else {
    out.setFrom(arg);
  }
  return rotate3(out);
}