Direct editing NurbsSurfaces vs. other surface types

Related to http://mcneel.myjetbrains.com/youtrack/issue/RH-29411 :

  1. Shrinking the surfaces in some cases doesn’t help.
  2. When the surfaces being editing are not NurbsSurfaces, the results may initially appear better, but control points outside of the trim sometimes show otherwise. Shrinking the surfaces after the edit may help.
  3. Further direct editing NurbsSurfaces can add control points even when not needed, e.g., stretching a cylindrical-shaped face along its axis.

Would some of the direct editing distortions be eliminated if Rhino maintained non-NurbsSurfaces and automatically converted NurbsSurfaces to RevSurfaces, etc., when possible during/after editing? This would also apply to commands such as _ExtendSrf that output NurbsSurfaces even when the input surfaces are not NurbsSurfaces.

Thank you,
Steve

direct editing fails 2.3dm (218.5 KB)