{HEAD ~ The distance} of {TAIL ~ each focus point} from the best fit surface is then calculated and the largest distance is compared to a predetermined value 
of
{ HEAD ~ The distance } of { TAIL ~ each focus point } from the best fit surface is then calculated and the largest distance is compared to a predetermined value
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH