PK_ERROR_code_t PK_SURF_make_sheet_trimmed
(
--- received arguments ---
PK_SURF_t surf, --- surface
PK_SURF_trim_data_t trim_data, --- trim data
double precision, --- precision for each edge
const PK_SURF_make_sheet_trimmed_o_t *options, --- options structure
--- returned arguments ---
PK_BODY_t *const body, --- sheet body
PK_check_state_t *const state --- state of body
)
Creates a sheet body given surface and trimmed SP-curve data.
Specific Errors:
PK_ERROR_bad_tolerance given edge precision too small
PK_ERROR_has_parent surface or sp-curves are not orphans
PK_ERROR_unsuitable_entity surface must be G1
PK_ERROR_not_on_surface sp-curve does not lie on surface
PK_ERROR_bad_sharing sp-curve is from another surface
This function creates a sheet body with a single face, given surface
geometry for the face and curve geometry for the edges.
The topology of the resulting sheet will be inferred from the geometry.
PK_SURF_make_sheet_trimmed is designed primarily for importing
geometric data of lower precision than Parasolid default.
The geometry supplied to the routine need not, therefore, conform to
Parasolid's standard precision. The user is responsible
for specifying the precision, the minimum distance two
points have to be apart to be regarded as distinct, which will be stored
with the edges of the resulting sheet body.
Received arguments:
surf will be the geometry attached to the single face of the body. It
can be of any type recognised by Parasolid, and must be orphan. If
surf is a B-surface, it must be capable of passing the continuity
checks imposed by PK_GEOM_check.
trim_data provides the trimming information. The spcurves in trim_data
are described here. For other information on trim_data see documentation for
PK_SURF_trim_data_t.
spcurves consists of an array of SP-curves which describe the boundary
loops of the trimmed surface. spcurves is not
allowed to be null, except in the case of a wholly
closed sheet with no loops e.g. whole sphere or torus.
Each curve appearing inspcurves must be an orphan.
Note that PK_SURF_make_sheet_trimmed will not incorporate
SP-curves representing surface degeneracies
into the model, as these have zero 3-space length.
Similarly trimmed SP-curves shorter than the requisite tolerance
(in terms of chord length) will not appear in the model
(closed SP-curve are excepted).
Note that two coincident opposing curves must be supplied
if a wire edge (corresponding, for example, to a seam on a periodic
surface) is required. In addition, PK_SURF_make_sheet_trimmed
will always create closed loop topology, regardless of
the actual geometric closure of the supplied loops of SP-curves.
All SP-curves must satisfy the continuity requirements
described under PK_SPCURVE_create before introduction
into a model by means of PK_SURF_make_sheet_trimmed.
The points stored on the vertices of the sheet body will be
computed by Parasolid, so the application has no need to
supply them. The position of the vertex is deemed to be the
centroid point of all the trimmed curve ends meeting at the vertex.
A suitable precision for the vertex is also computed.
It should be noted that because the vertex point and
precision are flexible to some extent, it is not necessary that
consecutive spcurves meet to within twice precision at the vertex.
As a safeguard against potentially incorrectly ordered data,
however, there will be a state code indicator returned when
any computed vertex tolerance exceeds 10 times precision.
The trim_set field in trim_data is ignored. The function may only be
passed a single trim_set.
If the resulting sheet body has its face normal in the wrong direction,
then this can be swapped with PK_BODY_reverse_orientation
precision is a 3-space distance parameter, and will be stored with all of the
edges of the resultant sheet. Refer to PK_EDGE_set_precision for the meaning
of this tolerance within a model. From an application point of view,
the value of precision will reflect the accuracy of the sending system's
curve data, and must be greater than or equal to Parasolid's linear tolerance.
PK_EDGE_set_precision can be used subsequently to modify the tolerance
of any edge of the resultant sheet.
checking option structure:
There are three optional levels of checking available on the resulting
sheet body. These can be employed by the application according to how much
is known about the input data in terms of, for example, the consistency of
the loops directions. Whichever option(s) used, PK_SURF_make_sheet_trimmed
will attempt to correct any inconsistencies found within the limits
imposed by the checks.
Note that each option is independent of the others.
check_wires : This option allows the identification of wire topologies
(e.g. seamlines) and will ensure that the
correct topology is made in such cases.
check_self_int : This option enables the application to pick up
self-intersections within the sheet. Checks made are:
. All edges are tested pairwise with each other to detect points at which
their fin curves intersect which are NOT model vertices. There is no
possible corrective action that can be taken here. Such sheets will fail
PK_BODY_check.
check_loops : This will check that the loops of the face are consistent.
With this option set to PK_LOGICAL_true checks are made to
check whether:
. The loops are correctly contained
(i.e. all inner hole loops lie within
the boundary or peripheral loop,
where such can be determined).
. The combination of loops is a valid
one for the surface type (for
example, a set of loops on a plane
contains just one peripheral positive
loop and the rest negative hole ones).
. If the above conditions are not met minimal corrective action is attempted.
In an attempt to create valid loops PK_SURF_make_sheet_trimmed
may reverse loops, and investigate singularities of surf introducing
them into the face as isolated vertices if necessary. This corrective
action is only attempted if check_loops is set to PK_LOGICAL_true,
and there no guarantee of valid result being found.
Returned arguments:
The resulting sheet is returned in body.
state is an indicator of the validity of the sheet after the chosen
checking options have been performed on it. It is not intended to give
detailed information (use PK_BODY_check for this). The returns are:
PK_BODY_state_ok_c: Indicates that either all selected checks passed,
and any attempted corrections were successful, or no checks were requested.
PK_FACE_state_redundant_c : Face is redundant with respect to the
supplied tolerances. This is because all the supplied curves were too short
with respect to precision for the production of a valid face.
PK_CURVE_state_inconsistent_c : Indicates that no sense could be made
of the input loops of curves. This means that they did not follow
round in the loop direction as indicated earlier, and there may be vertex
tolerances computed as a result which exceed 10 times precision.
PK_FACE_state_self_int_c : Indicates that the resultant sheet is
self-intersecting because edges meet at a place other than a model vertex.
PK_LOOP_state_invalid_c : Indicates that the loop structure of the
resulting sheet is in some way invalid (e.g. there is no peripheral
loop on a planar surface), and attempts to correct the problem failed.
Such sheets should NOT be subsequently incorporated into solid bodies.
PK_EDGE_state_bad_order_c : Indicates that the edges of the resulting sheet
are incorrectly ordered at at least one of its vertices. This can be caused
by the input data failing to comply with the convention on wire edges,
for example.
