PK_ERROR_code_t               PK_EDGE_ask_blend
(
--- received arguments ---
PK_EDGE_t                     edge,           --- an edge

--- returned arguments ---
PK_blend_type_t        *const type,           --- type of blend
PK_FACE_t              *const left_face,      --- face to left of edge
PK_FACE_t              *const right_face,     --- face to right of edge
PK_blend_edge_shape_t  *const edge_shape,     --- shape of blend
PK_blend_properties_t  *const properties,     --- blend properties
PK_EDGE_t              *const cliff_edge      --- cliff edge
)


This function returns information about the blend on a given edge if any.


Specific Errors:


If the edge has no unfixed blend the type is returned as
PK_blend_type_no_c and all other returned arguments are undefined.

rhos will be zero for rolling ball/chamfer/non-conic variable radius blends.
positions will be set to '(0 0 0) for rolling ball/chamfer blends.

The propagate flag in the properties field will always be returned as
PK_blend_propagate_no_c since this flag is only meaningful when the blend
attributes are created.

 The returned arguments are as follows:
    type        Type of blend, either PK_blend_type_no_c,
                                        PK_blend_type_ball_c or
                                        PK_blend_type_chamfer_c
    left_face   The face to the left of the edge.
    right_face  The face to the right of the edge.
    edge_shape  A structure detailing the shape of the blend on the edge of
                  type PK_blend_edge_shape_t.
    properties  A structure detailing the blends properties of type
                  PK_blend_properties_t.
    cliff_edge  Blend's cliff edge if used.

In the case of a variable radius blend, this function will only return the end
radii of the blend in edge_shape.