In gear-cutter CAD(Computer Aided Design), certain points belonging to series cutter loci which were generated by the simulation of the cutting process may form a gear-tooth profile. Finding out such points and analyzing them to predict the properties of a new gear is also a very important step which determines the succedent analyzing steps. However, the problem of abstracting these data from the loci rapidly and accurately remains to be solved. The two algorithms presented in this paper, concentric-arcs searching and revolving-scan searching, would provide theoretic basis for the on-line gear-tooth analysis. The former focuses on drawing concentric-arcs between the dedendum and addendum of the gear, the latter concentrates on drawing radial lines between two angles.Such arcs and lines will intersect one or more lines of the cutter profile.Correspongding screening criterions will greatly contribute to juge and identify useful intersections which may form the gear profile, and the gear-tooth shape analysis will be carried out as a result. Keyword: gear cutter; CAD; concentric-arcs searching; revolving-scan searching.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.