Hi Zooen,

re:
> If anyone knows how to make a "double solid" in MoI3D like the one I posted
> above, please explain to me how to do it.

In most places where that could occur it gets broken up into separate objects.

But one way to do it currently is with the new move face, if you move a face far enough that it divides the solid into 2 pieces you will get a brep object with a disjoint shell:






Sometime soon I'll be fixing it up to separate those into 2 separate solids.

re:
> But these are not disjoint FACES, it is a "double solid" of sorts.

Yes actually it's called a "disjoint shell". In CAD topology there is usually a topological container called a "shell" that has a list of faces in it. There isn't anything about the topology's structure that ensures that all faces are connected to each other.

- Michael