Thanks Johnny, I'm glad that you like the software!

Yeah, a problem with polys is they just do not trim or boolean as well, they will generate tiny slivered fragments too easily.

NURBS handles trimming in a very different way, kind of a "non-destructive" way. When you do a boolean or trimming operation on a NURBS object, the original surfaces actually stay there underneath everything, and new "trimming curves" are calculated. The trimming curves mark regions of the surface as being trimmed away. You can even erase those trimming curves later on to restore the underlying surface (MoI does this if you select all the boundary edges for a hole and then use delete).

This generally prevents things from degenerating into a bunch of tiny fragments after a few boolean operations. And the shading actually comes from the original underlying surface, so that shading stays accurate through different cuts.


Now on the other hand, polygonal subdivision surfaces are much better for handling highly organic objects that have a lot of little wrinkles and details in them, like a face for example. You have a lot more freedom for your point mesh arrangements with polygons, so when you are going to be manipulating surface points a lot, that's when they work a lot better.

So it is handy to have both sets of tools available to you so you can use the best one for any particular project.

- Michael