struct PK_FACE_section_o_s
    {
    int                       o_t_version;      --- version number
    PK_section_fence_t        fence;            --- (PK_section_fence_both_c)
    const PK_boolean_config_o_t
                             *configuration;    --- (NULL)
    const PK_boolean_region_select_o_t
                             *select_region;    --- (NULL)
    const PK_boolean_match_o_t
                             *matched_region;   --- (NULL)
    PK_LOGICAL_t              extend_face_list; --- (PK_LOGICAL_false)
    PK_LOGICAL_t              merge_imprinted;  --- (PK_LOGICAL_false)
    PK_LOGICAL_t              merge_new_faces;  --- (PK_LOGICAL_false)
    PK_LOGICAL_t              selective_merge;  --- (PK_LOGICAL_false)
    PK_section_check_fa_t     check_fa;         --- (PK_section_check_fa_yes_c)
    double                    default_tol;      --- (1.0E-5)
    double                    max_tol;          --- (0.0)
    PK_LOGICAL_t              tracking;         --- (PK_LOGICAL_false)
    PK_LOGICAL_t              keep_target_edges;  --- (PK_LOGICAL_false)
    };
typedef struct PK_FACE_section_o_s PK_FACE_section_o_t;




This option structure is supplied to a section operation for bodies.


Description of fields:



fence                  To determine which resultant bodies or faces are
                         returned when performing a sectioning
                         operation. Permitted values are :
                             PK_section_fence_front_c
                             PK_section_fence_back_c
                             PK_section_fence_both_c


configuration          Describes the configuration of target and tool
                         bodies.


select_region          Used to identify regions of the tool to include or
                         exclude in the result.


matched_region         Describes matched regions between the target face and
                         the tool sheet.


extend_face_list       A face section receives a subset of the faces of a
                         target body. If the imprinting phase of the section
                         results in incomplete loops of imprinted edges, then
                         additional target faces will be used.


merge_imprinted        Merge all mergeable imprinted edges created and/or
                         located by the section operation.
                         Note the following :
                          o an existing edge can be considered an imprinted
                            edge if it forms part of the intersection between
                            faces from the target and tool.
                          o mergeable edges which are adjacent to new section
                            faces are not merged (this behaviour is particular
                            to sectioning).



merge_new_faces        Merge all mergeable imprinted edges created by
                         the section operation including edges which are
                         adjacent to new section faces. This flag has no
                         effect if the merge_imprinted field is not set
                         to PK_LOGICAL_true.



selective_merge        If this is set to PK_LOGICAL_true, the merge phase
                         will avoid mergeing imprinted edges that existed
                         and were mergeable before the start of the section.
                         This flag has no effect if merge_imprinted is not
                         set to PK_LOGICAL_true.


check_fa               The value of this determines if face checking is
                         performed during the operation, permitted values
                         are :

                         PK_section_check_fa_no_c
                         PK_section_check_fa_yes_c

                         The default is set to PK_section_check_fa_yes_c
                         and it is strongly advised not to change this value.
                         If the face checking is switched off, the section
                         operation may produce an invalid body without
                         raising an error.


default_tol            The default tolerance to which the sectioning
                         operation, if it has to, may approximate entities
                         or assume that entities are coincident. This value
                         should be set to a value that is related to the
                         tolerance to which the application is creating
                         approximations.
                         If this field is set to zero (0.0), it is assumed
                         that the decision to set tolerances on entities is
                         being left to the modeller.


max_tol                This value specifies the maximum tolerance which may
                         be applied to any entity involved in the sectioning
                         operation.
                         If this field is set to zero (0.0), the default, then
                         it assumed that no upper limit has been set on the
                         tolerance of any entity.
                         If the field is not set to zero (0.0), then it must be
                         set to a value that is greater than the value of the
                         default_tol field.


tracking               Not currently in use.


keep_target_edges      This option controls which edge survives when a
                         target edge and a tool edge coincide in a boolean. If
                         both faces adjacent to the tool edge survive, then the
                         tool edge will also survive. Otherwise, the result
                         depends on the setting of the option:

                         PK_LOGICAL_true:
                             The target edge survives, unless the target edge
                             is a new edge imprinted during the boolean, and
                             the tool edge is an original edge - in this case,
                             the tool edge survives.

                         PK_LOGICAL_false (the default):
                             The older edge (i.e. the one with the smaller tag)
                             survives.

                         This option only has an effect if general topology
                         is disabled. If it is enabled, then the target edge
                         will always survive, even if it is a newly imprinted
                         edge.