struct PK_EDGE_types_s
    {
    PK_EDGE_vertex_type_t   vertex_type; --- types of vertices on edge
    PK_enclosure_t          enclosure;   --- types of regions surrounding edge
    PK_EDGE_fins_type_t     fins_type;   --- number of fins on edge
    };

typedef struct PK_EDGE_types_s PK_EDGE_ask_type_t;





This structure contains classification data for an edge.


This structure contains data for a given edge that classifies it according
to whether it is:
    (a)     open, closed, or a ring.
    (b)     surrounded by solid regions, by void regions, or by both.
    (c)     wireframe, laminar, normal, or general.



vertex_type   Whether the edge is open, closed, or a ring.
              Values can be:
                PK_EDGE_type_open_c
                PK_EDGE_type_closed_c
                PK_EDGE_type_ring_c


enclosure     What types of regions the edge is surrounded by.
              Values can be:
                PK_enclosure_inside_c
                PK_enclosure_outside_c
                PK_enclosure_on_c


fins_type     The type of the edge.
              Values can be:
                PK_EDGE_type_wireframe_c
                PK_EDGE_type_laminar_c
                PK_EDGE_type_normal_c
                PK_EDGE_type_general_c