PK_ERROR_code_t      PK_FACE_imprint_cus_isoclin
(
--- received arguments ---
int                  n_rec_faces,   --- number of received faces (>0)
const PK_FACE_t      rec_faces[],   --- received faces
PK_VECTOR1_t         direction,     --- isocline direction
double               angle,         --- isocline angle
double               tolerance,     --- max tol for applying surfs
const PK_FACE_imprint_cus_isoclin_o_t *options,
                                    --- options structure

--- returned arguments ---
int           *const n_ret_faces,   --- number of returned faces (>=0)
PK_FACE_t    **const ret_faces,     --- returned faces
PK_LOGICAL_t **const is_steep,      --- whether faces are steep
int           *const n_edges,       --- number of new edges      (>=0)
PK_EDGE_t    **const edges          --- new edges
)


This function creates and imprints isocline curves on a given set of faces.


The isocline is specified by a direction and an angle.

The function may, at times, have to use approximate geometry.
For such cases, tolerance specifies an upper bound on the distance by which
a point on the actual geometry may deviate from its ideal position.
While the function will usually satisfy this constraint, it is not guaranteed.

The set of rec_faces must all come from the same body.
The set ret_faces is the union of rec_faces and any newly created faces.
In ret_faces, each given face from rec_faces is immediately followed by
any additional faces that have been created from it.  By definition, each face
in ret_faces is not steep or all steep.  `is_steep[i]' reports whether
`ret_faces[i]' is steep.

The new edges created are returned in edges.