NURBS > Relax Surfaces (selectable after NURBS > Fit Surfaces, but not for NURBS surfaces whose Fitting Method was Adaptive) smoothes the NURBS surface by relaxing the NURBS control points independently of the underlying polygons — even over rough polygon structure.
The parameters are:
Iterations integer field - specifies a number of relaxation processes to be performed consecutively.
Strength decimal field (0.0 to 1.0) - specifies a strength of the relaxation process.
OK button - saves relaxed NURBS surfaces to the object and closes the dialog.
Cancel button - terminates the dialog without saving relaxed surfaces.
Execute button - performs the relaxation process as configured by the Iterations and Strength fields.