def length
      return max_point.x - min_point.x, max_point.y - min_point.y, max_point.z - min_point.z
    end
def length
      return max_point.x - min_point.x, max_point.y - min_point.y, max_point.z - min_point.z
    end
[Output]
  return width, height, depth as [Numeric, Numeric, Numeric]