Hi Bravlin, same thing - NURBS models are not generally editable in all areas by control point editing, because of the "underlying surface" and "trim curve" concepts that we talked about previously. That's where after a boolean operation between 2 objects, the surface geometry does not change and only new trim curves are created. That means that you have 2 surfaces that have different control point structures that kind of pass through each other and don't share a common set of control points along their topological joined edge unlike with polygon modeling.

Since NURBS solids are not generally editable by control point manipulation it follows that editing surfaces by control point manipulation is not a focus for CAD programs.

A CAD program is not the right kind of tool for that kind of modeling strategy, there are other tools that do focus on it and do a better job than what a CAD program could do.

CAD programs are strong in different areas like being able to form models from a small number of 2D profile curves using boolean operations.

- Michael