PK_facet_shape_t   


typedef int PK_facet_shape_t;


    PK_facet_shape_any_c         : allow creation of holed or concave facets
    PK_facet_shape_cut_c         : cut facets with holes into concave facets
    PK_facet_shape_convex_c      : divide concave facets into convex facets