I've found that if you have the Top Level Assy open in the background when you copy, paste, rename, relink and open the new drawing, the Assy isn't affected.
However, I consider this to be a bit of a work around as the Top Level Assy is quite large and would prefer to have it closed down if I can.
If anyone has an answer to the original question, I'd still appreciate a response
If you have the drawing open that references the top level asm then SW has it open but hidden. So opening the ASM even if it is large should not a big deal. It's already in memory unless you work with loading specified pages or that kind of thing.
It depends how you change the references. Do you do it going into File references dialog before opening your new drawing or do a save as change the references their? In this case SW replace the references (default behaviour) in all open files (shown or hidden). And that is what you see. Now since you know that behaviour you can simply open the hidden top level asm and do a "reload" and you original file references will be fixed again.
Another approach would be to copy paste the drawing & sub asm in your file explorer. Then open the drawing and replace the file reference for the views that reference the old sub asm.
Or you can search the forum Matt Gjertson. He offered a solution to automate your process without the file reference issues.
Hi Elmar, sorry, you've misunderstood. The problem is that I'm changing the drawing references and it's updating the assembly references as well.
I'm sure this is a glitch as I've not told the assembly to swap assemblies out. It's as if I've changed the drawing references, so instead of looking for Assy 1 I've changed it to look at Assy 2, and then it's gone into the assembly and done a Replace Component on Assy 1 for Assy 2?!?
I think I did understand. As per your description below it's a default SW behavior.
""...This is all well and good and I've been changing the references of copied drawings for years. The problem I'm having today is that when the drawing opens after just changing the references, it also seems to replace Sub Assy 1 with Sub Assy 2 within the Top Level Assy!?"
If the Top Level Assy wasn't open at time when you change references than you would be okay. The problem is that you have a drawing view in your open sub assy drawing that references the top level assy. That means your top level assy is in memory, even though it's not visibly open. That makes no difference to SW whether you see it, cause SW sees it if it is loaded. And loaded it is.
I can see that you don't want this behavior. I can also see that it might be confusing to the user if you don't have awareness of the limitation to the change reference function.
I hope that helps explain it.