Hi ELF, to answer your earlier questions:

> When you boolean with NURBS, you simply use a curve to mask out part of
> surface in a hierarchial fashion

Yes, this is correct - during the boolean the curves where different surfaces intersect is calculated, and then those curves as used as new "trim curves" on the existing surfaces. Trim curves are used as a way to mask out different portions of a surface.


> So there is no way (even for the developers) to take such a bunch of surfaces
> that has been joined together to form a solid, and "collapse" it to an object with
> control points ad the edges.

Yes, this is correct, except in the special case where the trim curve happens to be running parallel to one of the natural edges of the underlying surface.


> Is it possible to make a joined surface, like a surface that is only described by
> control points found on this surface, like points along the edge of the "hole".

No, there is no easy way in general to recalculate the surface to have its points matching the trim curves.

To do it would require a very significant reconstruction of the surface to a totally different shape, it would be very difficult to do this well.

Here is a more general example that shows how difficult this would be:



Here the surface is very simple, just 4 control points forming a simple plane. But you can see how complex the trim curves can be on the surface - there is no easy way to just transform those 4 control points and have them match all those complex edges in the trimming curves.

- Michael