With VectorWorks 12.5 you will find it easier to edit the objects that can be…
Vectorworks Tip 403 – Editing Slabs That Have Used 3D Object Modifiers
Editing Slabs That have used 3D objects. If you have used 3-D objects to edit your slab, you can right click on the slab and choose edit modifiers. You can change the location or some of the parameters (on the Object Info palette) but you are not able to change the shape of the original objects used to create the 3-D object, and you are not able to change or add additional 3-D objects. it.