S-F pinda filtreeritakse Nis paigutusindeksiga, et eemaldada pinnalt lühemad lainepikkused, siis pind on samaväärne "primaarpinnaga", või filtreeritakse Nic paigutusindeksiga, et eraldada pikemad lainepikkused lühematest, pind on siis samaväärne "lainelisuspinnaga".
S-F surface is filtered with Nis nesting index to remove the shortest wavelengts from surface, the surface is equivalent to a "primary surface" or is filtered with Nic nesting index to separate longer from shorter wavelenths, the surface is equivalent to a "waviness surface".
