may be you need more understanding of 3d graphics. there are two types of 3d facility available in auto cad. one is solid and the other is surface. wire frame is only the way of representation of the object. autocad creates the object and it shows the object with wire frame. it is not ordinary lines or circles which you can edit. a 3d object is a single piece. like sphere, cylinder or cone or it can be combinations also. auto cad help also contains lot of examples.