transformed3 method
Transform a copy of arg of type Vector3 using the transformation
defined by this. If a out parameter is supplied, the copy is stored in
out.
Implementation
Vector3 transformed3(Vector3 arg, [Vector3? out]) {
  if (out == null) {
    out = Vector3.copy(arg);
  } else {
    out.setFrom(arg);
  }
  return transform3(out);
}