re: import STL / OBJ

This is not very easy to do, since STL and OBJ contain faceted polygon geometry, not smooth NURBS geometry like MoI is set up to work with.

MoI exports to these formats by taking its smooth surface sheets and dicing them up into facets. But it is not easy to do the reverse and take facets and make smooth sheets out of them.

It's kind of like how you can chop up carrots to make a stew, but you can't easily take a stew and make carrots out of it...

Eventually it might be possible for me to add polygon mesh objects as a different type of geometry that you can work with inside of MoI. But it is difficult to add those and have the current toolset work with them (such as booleans and trims), so for a while I have focused on only providing smooth (NURBS) surfaces inside of MoI.

- Michael