Apply jitter (deformation) to surface

trying to add slight deformation (jitter, cloth like, etc) to a surface.
but need the border to stay intact, how would I ignore all the points
along the surface border ? or is there a better way to do this ?

Apply jitter (deformation) to (11.6 KB)


very cool! I was trying to use InCurve somehow to make it work.
big thnx!