About Reparam Curves and Soft Points
You can add reparameterization curves to minimize surface twisting and the distortion of isolines. When you drag a reparameterization curve along a surface, you modify the isolines to change the surface shape. Enter Reparameterization mode during surface creation or when you redefine the surface.
The endpoints of reparameterization curves are soft points, and they lie on the surface boundary curves. You can select a location reference for the soft points, enter a value to position them, or drag them into position. Soft points are not created at the intersections between reparameterization curves. Reparameterization curve soft points are automatically updated when you add, modify, or delete curves to define a surface.