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