code: public boolean contains(Envelope3D other) {// Note: Will return False, if either envelope is empty.
  		return other.xmin >= xmin && other.xmax <= xmax && other.ymin >= ymin && other.ymax <= ymax && other.zmin >= zmin && other.zmax <= zmax;
  	}
docs: Returns True if the envelope contains the other envelope (boundary
  inclusive).