How can I subdivide a Surface NURB without affecting the shape? Say, I lay down a Surface NURB Circle in Blender.  It has 4 control points, and it is circular.  Now, if I Subdivide it to add more control points, it starts to become a square.  The more I subdivide the more square it becomes:



What I'd like to know is if there is a way to subdivide the original circle and have Blender add new control points such that the original circular shape is preserved.  Same goes for any Surface NURB.  I'd like to be able to add new control points without destroying the shape of the curve.
I am afraid that's not how nurbs are design to work. The way nurbs are suppose to function is to use the least amount of point to describe a curve. Every quarter of a circle is a simple arc and would be suffice to have 3 points in order to describe it.

Is there a reason behind your question that you would care to elaborate? So we may figure out a better way to do if ... if any.