寻找洞孔

After an object or a part is localised, we can comfortably find holes of the desired form and size. It is very easy to do a "virtual negation" of the 3D shape which converts the holes -- previously empty volumes, now filled -- into objects. Since we already know how to localise objects of various forms, we can now localise the holes as objects of appropriate size. 在物体或零件被定位后，我们可以方便地找到想找的形状和尺寸的孔。对3D形态进行“虚实转换”非常容易，将孔中先前为空的体积（现在已填充）转换为物体。由于我们已经知道如何定位各种形态的物体，因此我们现在可以将这些孔视为应有大小的物体来定位。