So, this is a question I've had for some time.

As far as I know, the Assembly Symmetry mechanism is similar both in CATIA V5 and CATIA 3DEXPERIENCE. 

Imagine a simple situation: I have a simple part, which is under a product, and I want to mirror it by one of the assembly planes. The goal of mirroring is to generate a second instance of the original part, not a new reference. A fairly common situation, I believe.

And it seems I just can't make that. If I select the "New Instance" option, it will generate a mandatory 2-plane joint symmetry. Why is that so? I checked the available documentation, and it allowed me to understand the way this works, but not why it was conceived that way. I'm asking that because I don't have a good use case for this (for example, when customers ask me). Also, I've seen numerous examples in YouTube of custom-developed assembly symmetry macros, which leads me to believe that the standard behaviour is not what clients want.

Thanks in advance, 

Pedro Delgado