Hi okapi, I'm not so sure about just directly copying the way that Rhino handles parent/child layers, it's kind of weird in some ways.

In particular I don't like how in Rhino the parent layer has its own color setting which when set has no effect on the child at all. Having a parent/child relationship like that makes it seem like there should be some kind of inheritence happening with stuff like materials or color properties but then there isn't.

It seems like a cleaner idea for that kind of grouping mechanism would be to have folders where you could make a folder to contain items and collapse things, rather than trying to make an actual style for the parent object.

But a folder mechanism like that may not be compatible with Rhino's parent/child layer structure, so I'm not sure about being able to transfer that structure back and forth from MoI to Rhino.

One big potential thing for a folder mechanism is that maybe it could be used as a general purpose organizer thing throughout the scene browser, like in the future there will probably be many other sections in the scene browser like "named views", "saved cplanes", etc... and having one general mechanism to organize that stuff with folders would be nice.

There was some previous discussion of this here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3415.1

- Michael