struct PK_CURVE_intersect_curve_o_s { int o_t_version; --- version number of option structure PK_LOGICAL_t have_box; --- whether box provided (PK_LOGICAL_false) PK_BOX_t box; --- box of interest PK_SURF_t common_surf; --- surf containing curves or --- PK_ENTITY_null (PK_ENTITY_null) }; typedef struct PK_CURVE_intersect_curve_o_s PK_CURVE_intersect_curve_o_t; Holds optional controls on intersections between two curves. The option structure defines options applicable to the intersection of two curves.