The deep clone and wblock clone operations actually consist of two steps: cloning and translating. The cloning step is where dwgOut() and dwgIn() are called and the objects are copied. The second step is the translation step, which uses the ID map to relink all the objects to reflect the new relationships.
During translation, all four types of object IDs have to be translated. Some objects have been cloned and are in the ID map, while others have not been cloned and are not in the map. During ID translation, if an ID pair corresponding to the reference is not found in the ID map, one of two things happens. If the reference is in the same database as the object that is referring to it, it is left alone. Otherwise, it is set to NULL. See Translation Phase.