I have a part that has several instances. With toolkit I am opening one of those instances and retrieving a simp rep. Then I output an ACIS file and then I want to clear my memory of everything except the generic part that I started with. How do I do this? I am unable to successfully call ProFaminstanceErase I think because I have a simp rep of the instance open. However when I call ProMdlErase on the ProPart simp rep handle it crashes Pro. Can someone give me some advice on activating/retrieving a simp rep of an instance of a part and then erasing it? Here is my code to output the ACIS file. I am not trying to erase the instance in the function. I try and erase the instance in the calling function.