不太懂「建築物是像千層派一樣往上疊而不是切蛋糕後在重新在同一層排列」的意思？我看維基是寫說「avoid overlapping 3D volumes – especially if the volumes have common faces. 」應該是切開來排列吧...
Reference: https://wiki.openstreetmap.org/wiki/Simple_3D_Buildings#Building_parts