Hi Matadem, it's generally better to do surface control point modification in a polygon subd modeling program and not in NURBS.
The main reason why is that in a polygon modeler you can add in a single individual new vertex anywhere you want and hook up polygons to it.
The way NURBS surfaces are set up they are defined by a grid of points in rows and columns. So you can only add in a new full row or column into the control point grid, you can't add just a single point.
NURBS surfaces are strong in different areas than that, especially with Booleans because NURBS has the concept of a "trimmed surface" where there is an underlying surface that has a trim boundary. So when you do a boolean on a NURBS model the underlying surfaces remain the same and just the trim boundaries are changed. Polygon modeling doesn't have that concept, when you do booleans in a polygon modeling program the geometry gets diced up into more and more little fragments.
But if you want to experiment and get a lower density surface without regard to how accurately it keeps the shape of the original, you could use this process:
(which again I don't recommend doing, you are better off doing modeling by surface control point manipulation in a poly modeling app)
Select one edge of your surface:
Use Ctrl+A to select all edges:
Use Delete to erase the trim boundaries and recover the full underlying surface:
Select the surface and run Construct > Curve > Iso and make some isocurves in the U direction:
Add more isocurves in the V direction of the surface:
Select the outer 4 boundary curves of the surface and use Ctrl+C/Ctrl+V to duplicate them as standalone curves.
You now have a grid of curves, you can delete or hide the original surface and select your new grid and run Construct > Network to build a surface from it.
Set the options for the Network command to have "Mode:uniform" and "Point count:1".
You will now have a surface that approximates the shape of the original but will have a density only driven by how many U and V isocurves you extract and not connected to the original surface's control points:
But don't do this - a CAD program is not the right tool for this type of work. If you want to model by sculpting a 3D point cage do it in a Poly modeling app where everything is tuned for doing that.
- Michael
