Abstract: Preferably, the spatial coordinates of a surface are determined by an optical method comprising scanning the surface with an incident beam of light from a scanner head, determining the range to the surface at a plurality of points on the surface relative to the scanner head by a means of a return beam reflected from the surface, determining the relative spatial location and orientation of the scanner head at the time of scanning each of said plurality of surface points by a remote optical sensing system that includes a plurality of positioning sensors each located at a different known location relative to the other positioning sensors and a plurality of markers attached to the scanner head, with each marker at a at different location relative to the other markers.