When you combine the instant push/pull technique on planar objects with Automatic Working Planes, you get a very quick way to do 3D modelling. In step one you draw your planar object on the automatic working plan. In step two you move to the planar object, it should highlight. In step three you pull your planar object through your model. In step four, hold down the alt/option key and click. Vectorworks will use your new extrusion object to subtract from the original object.