Hi Gav,

> Yep, and that's where sometimes I've had to stop and
> think 'what now' :-).

Well, usually it is just repeat more of the same process - draw in some new profile curves, create some new solids from those by whatever method is suitable for the shape, like extrude, sweep, revolve, etc... then combine those new solids with other ones by booleans.

Also instead of creating a solid sometimes you will draw in curves and use the curves to cut away pieces of the solid to make a new shape.


> One of those things that time and experience will show I guess.

Yeah, kind of - one thing that may help is to imagine more about how some part would be manufactured.

When some kind of steel part is manufactured by machining, it does not get built in a factory by some machine pulling vertices around, instead there may be things like drills that cut away material from some stock or cut holes in things and so forth (of course there are quite a variety of different manufacturing methods, but that may help with some ideas).

So if you want to have a hole in something, with NURBS you want to model the main piece without the hole first, and then make the hole by cutting the object with a boolean operation. That's instead of trying to make holes by something like moving a bunch of vertices to kind of follow a path around the hole.


It's definitely a very different approach from polygon modeling, but actually that's why it is useful! If it just behaved the same as polygon modeling then there would be no benefit to you to use it instead of polygon modeling. By it having a different approach, that makes it have different strengths and weaknesses and if you use it situations that leverage its strengths that's when you can save a lot of time.

- Michael