I _know_ what a feature tree is, I use fusion every couple weeks. CAD is not some magical hard thing to do, except perhaps for more complex parts where it's a software problem (like mirroring the features of a surface to the other side but being unable to flip them...thus text is mirrored, thanks Fusion). Constraints are indeed a pain in the ass but that's literally their purpose.

And my opinion is still that an LLM could rough out a simple model just fine. It won't be designing engine parts any time soon but simple parts I still reckon it could rough 'em out.