> P.S any plans to have some kind of mating relationships (concentric,
> parallel, distance) in the future?

I haven't really thought very much about that...

It will probably be difficult for me to get into a full constraint solver type thing, but I think what you are talking about here could possibly be easier than that. It might be workable as a specialized transformation command. But it will probably take a while before I can get to that.

- Michael