FIGURE 3. Measuring the angle between the buccal side surface and the buccal side enamel edge (FMNH-945/1960, D. bicornis). 1. line representing the direction of the enamel edge (normal of bisecting plane); 2. half the model, after bisection; 3. the remaining model is zoomed and rotated so that the normal coincides with the viewing direction; 4. measurement of the angle alpha.