typedef int PK_pick_approximate_t; The 'pick_approx' option can be set to one of the following values: PK_pick_approximate_yes_c Curves are approximated by a sequence of straight line chords. PK_pick_approximate_no_c Accurate curve geometry is used when checking whether the ray intersects a face. The default value is PK_pick_approximate_yes_c and it is recommended for interactive picking operations.