ENEXEN ( entity, dir1, dir2, dir3, posn, ext, ifail )
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Enquire extreme point of entity
Receives:
KI_tag_topology *entity --- face or edge
KI_vec_direction dir1 --- first direction
KI_vec_direction dir2 --- second direction
KI_vec_direction dir3 --- third direction
Returns:
KI_vec_position posn --- position of extreme point
KI_tag_topology *ext --- face, edge or vertex on
--- which extreme lies
KI_cod_error *ifail --- failure indicator
Specific errors:
KI_cant_find_extreme failure
KI_missing_geom entity has missing geometry
KI_wrong_entity entity is not a face or an edge
KI_coplanar directions are coplanar
Description:
The entity must be a face or an edge.
The extreme point on the face or edge which is furthest in the direction
'dir1' is returned, unless there is more than one such point, in which case
'dir2' and 'dir3' are used successively to reduce the number of extreme
points to one.
If the extreme point lies on a vertex or an edge, this is returned in 'ext'.
Otherwise the face is returned.
The entity must not have missing geometry.
The three directions must not be coplanar.
