PK_ERROR_code_t                        PK_BODY_make_curves_outline
(
--- received arguments ---
const int                              n_bodies,        --- number of bodies
const PK_BODY_t                        bodies[],        --- bodies
const PK_TRANSF_t                      transfs[],       --- body transformation
const PK_VECTOR1_t                     view_direction,  --- viewing direction
const PK_BODY_make_curves_outline_o_t *options,         --- option structure

--- returned arguments ---
int                             *const n_curves,        --- number of curves
PK_CURVE_t                     **const curves,          --- boundary curves
PK_INTERVAL_t                  **const intervals,       --- parametric
                                                        --- interval
                                                        --- of curves
PK_TOPOL_t                     **const topols,          --- edges/faces of
                                                        --- curves
int                            **const outlines,        --- indicates which
                                                        --- curves belong to
                                                        --- which outline
double                         **const curve_tolerances,--- curve tolerance
double                          *const max_separation   --- largest gap
                                                        --- between adjacent
                                                        --- ends of the curves
)


This function outputs one or more outlines of a body or bodies for a given
view direction as a set of ordered curves together with their intervals.


Specific Errors:
    PK_ERROR_bad_component          transfs is inappropriate
    PK_ERROR_unsuitable_entity      body is not a sheet or a solid body
    PK_ERROR_non_manifold           Outline is non-manifold
    PK_ERROR_failed_to_make_outline Function failure


The function is only implemented for entities of type PK_BODY_type_solid_c or
PK_BODY_type_sheet_c.

PK_ERROR_non_manifold will be returned if any part of the outline does not
consist of a closed loop with non-empty interior. This could happen if
a portion of a sheet body is edge-on in the view direction for example.

If the 'transfs' argument is NULL, no transforms are applied to the bodies and
the bodies array must not contain duplicates.

If the transfs argument is not NULL, it refers to an array of n_bodies
PK_TRANSF_t entities. Each body is transformed by its corresponding entry in
'transfs'. The bodies array may contain duplicates. Instancing transforms may
contain translation and rotation but not perspective terms. If an instance does
not need to be transformed, its 'transfs' entry can be set 'PK_ENTITY_null'.

topols returns the edges or faces of these curves.
    An edge is returned when it coincides with an edge.
    A face is returned when its outline is a silhouette curve of that face.

The one or more outlines of the body or bodies are represented by the curves
and their intervals which make up the boundary(s) of the body(s) for the given
view direction. The curves are returned as a set of ordered curves such that
the body, when viewed in the view direction, lies to the left of the curve when
looking in the direction of the curve. When two or more bodies overlap in the
view direction, the outline will be that of the combination of the bodies.

outlines returns a set of integers indicating which curves belong to which
outline. For instance if this function was used on a body with a hole in it
and 9 curves were returned, 5 of which belonged to the outer outline and 4 to
the inner outline then 'outlines' would return ( 0 0 0 0 0 1 1 1 1 ).

Note: Where the function returns several outlines the order of those outlines
is undefined.

curve_tolerances returns the accuracy to which each curve represents the
outline.

When modelling with tolerant bodies the curves will meet to tolerance and gaps
may occur. max_separation will return the largest gap between the ends of
the adjacent curves.