Hi Warren, you're welcome!

> Random question : Are the bolded lines important in terms of how easily one will be able to work with
> the mesh? Like, should I be trying to hide those behind other geometry when possible or anything like
> that? Or are they purely decorative?

Well, they're not exactly decorative - they're a normal part of the NURBS geometry. The way NURBS objects work is you have a bunch of surfaces and those surfaces have "trimming boundaries" on them that define which areas of the surface are active and which part of the surface are holes or cut away portions.

When you do boolean operations the actual "underlying surfaces" stay the same and only new trimming boundaries are created that then trim away more parts of the surface area.

Those bolded lines are the edges of your model, the edges are what make up the trimming boundaries.

It's a pretty different geometry system than a polygon mesh object, with a polygon mesh your object is made up of all little facet elements and there isn't this same concept of a bigger "underlying surface" and "trimming boundaries".

So it's not like you necessarily want to get rid of those, it's normal for your objects to be made up of various trimmed surfaces.

- Michael