Reverse in U, Reverse in V
Reverses the direction of the U or V parameter, i.e the first line of the control polygon U=0 is now U=Max and vice versa. Simularly for V. Point locations remain the same it is only the order of the point columns/rows within the control polygon that are changed.
Flip in U-V
Swaps the U and V directions of the surface. Point locations remain the same it is only the order of the point columns/rows within the control polygon that are changed.