RRVIND ( nopts, iopts, optdta, entys, transf, ifail )
=====================================================
Generate view independent rendering data.
Receives:
<KI_int_nitems> *nopts --- number of options in 'iopts'
KI_cod_rrop iopts[nopts] --- rendering options
<KI_tag_list_dbl> optdta[nopts] --- option data lists
KI_tag_list_entity *entys --- entities to render
<KI_tag_list_<transform>> *transf --- entity transforms
Returns:
KI_cod_error *ifail --- failure indicator
Specific errors:
KI_missing_geom A topological entity has no associated geometry
KI_abort_from_go Rendering aborted by GO
KI_wrong_transf Unsuitable transform
KI_not_same_length Entity and transform lists are of different lengths
KI_wrong_entity_in_list Entity is not a part, face, edge or geometry.
KI_bad_option_data Option data incorrect for specified options
Description:
RRVIND outputs, through the Graphical Output interface (GO), data for a
picture of the entities which is independent of the viewing angle and
distance.
RRVIND can render assemblies, bodies, faces, edges, B-Curves
and B-Surfaces, foreign geometry and offsets of B-surfaces and foreign
geometry.
Transforms may only contain translation and rotation components. Reflections,
scales and shears are not allowed.
The data output is selected by options in 'iopts'. For some options the output
is further controlled by data in a real list whose tag is passed in the
corresponding entry in 'optdta'. If no data is required for an option a null
tag should be passed.
Options accepted are:-
Option Contents of option data
===================================================================
RROPED: EDge-data none
RROPTR: TRansform none
RROPSM: SMooth-edges none
RROPIE: Internal Edge none
RROPPC: B-Curve (Bezier) none
RROPNC: B-Curve (Nurbs) none
RROPPH: Planar-Hatch (1) Planar hatch spacing in model units
(2,3,4) Normal direction of hatch planes
(5,6,7) Plane coordinate (omissible)
RROPRH: Radial-Hatch (1) Hatch spacing in radians around 'spine'
(2) Hatch spacing in model units along 'spine'
(3) Hatch spacing in radians about centre
RROPPA: PAra-Hatch (1) Hatch spacing along u
(2) Hatch spacing along v
RROPUB: Unfixed-Blends (1) Rendering style:-
1 => Draw as specified in model
2 => Draw blend boundaries
3 => Draw blend boundaries and rib lines
(2) Rib spacing in model units
(only required for style 3)
RROPCT: Curve Tolerance (1) Chord tolerance in model units
(2) Maximum chord length in model units
(3) Angular tolerance in radians
RROPVP: ViewPort (1,2,3) Centre of viewport in model coordinates
(4,5,6) 1st axis of viewport in model
coordinates
(7,8,9) 2nd axis
(10,11,12) 3rd axis
(13) Length of viewport along 1st axis in model
units
(14) Length along 2nd axis
(15) Length along 3rd axis
When rendering B-Curves and surfaces, only the following options
are relevant:-
RROPTR, RROPPC, RROPNC, RROPPA and RROPCT.
The default for these types is to render the boundary, for a surface, and
the curve for a curve. Therefore, in contrast to the other entity types,
output will be generated even in the absence of any accompanying options.
Option RROPED causes output of data for edges in the model.
Option RROPTR is required if any of the entities is to be rendered in a
transformed position (e.g. as part of an assembly). If it is not specified,
the contents of 'transf' are ignored, and entities are rendered in their
local coordinate system.
Option RROPSM causes the output data for an edge to specify whether or not
the edge is 'smooth' (i.e. the faces have the same tangent surface at the
edge); the calling program may then choose to omit smooth edges from the
final drawing. If RROPSM is not specified, the smoothness parameter is
returned "unknown" for all edges.
Option RROPIE causes the output data for an edge to specify whether or not
the edge is internal to a surface; i.e. the faces on either side of the edge
lie on the same surface. This will be the case if the edge is an internal one
between patches on a B-Surface, or is mergeable. The calling program
may then choose to omit internal edges from the final drawing.
If RROPIE is not specified, the internal edge parameter will be "unknown"
for all edges.
Option RROPPC causes the data for a B-Curve (type TYCUPA) to be
output in Bezier form.
Option RROPNC causes the data for a B-Curve (type TYCUPA) to be
output in NURBS format.
The default, if neither RROPPC or RROPNC is selected, is to output
the data for B-Curves as a poly-line. These options both apply to
derived B-Curves as well. For example, hatch and boundary lines on
B-Surfaces.
Note that at most one of RROPPC and RROPNC may be selected.
Option RROPPH causes planar hatch lines to be output. If no option data is
given faces which have a planar hatching attribute set will be hatched as
specified by that attribute. If a hatch specification is given in the option
data all faces not otherwise hatched by use of the RROPRH and RROPPA options
will be hatched according to that specification.
Option RROPRH causes radial hatch lines to be output for faces with standard
curved surfaces (cylindrical, conical, spherical, toroidal) or blending
surfaces. If no option data is given those faces which have a radial hatching
attribute set will be hatched as specified by that attribute. If a hatching
specification is given in the option data all faces with standard curved
surfaces or blending surfaces will be hatched according to that
specification.
The values given in the option data are interpreted according to the type
of surface to which they are applied as follows:
Cylindrical and Conical surfaces:
The first value controls the spacing of straight hatch lines running
along the surface parallel to the axis. Such lines would be generated
by a plane rotating in steps about the axis by the given angle.
This angle must be in the range 0 to two pi.
The second value controls the spacing of circular hatch lines running
around the surface perpendicular to the axis. Such lines would be
generated by a plane stepping along the axis by the given distance.
The third value is not significant.
Spherical surfaces:
The hatching of spherical surfaces is related to an axis passing
through the centre of the surface and parallel to the Z axis.
The first value controls the spacing of the 'longitudinal' hatch
lines, as would be generated by a plane rotating by the given angle
about the axis of the surface. This angle must be in the range 0 to
two pi.
The third value controls the spacing of the 'latitudinal' hatch lines,
as would be generated by a cone (apex at centre of surface, axis
parallel to surface axis) whose half angle is incremented by the given
value. This value must be in the range 0 to two pi.
The second value is not significant.
Torus:
The first value controls the spacing of circular hatch lines centered
on the axis of the torus, as would be generated by a cone (axis
parallel to torus axis, passing through spine of torus) whose half
angle is incremented by the given value. This value must be in the
range 0 to two pi.
The second and third values control the spacing of circular hatch
lines centered on the spine of the torus, as would be generated by a
plane rotating about the axis of the torus. The second value specifies
a distance along the spine whereas the third value specifies an angle
about the axis. If both second and third values are given the second
value is ignored. If a third value is given, it must be in the range
0 to two pi.
Edge-Blend surfaces:
The second value controls the spacing of 'circular' hatch lines running
around the surface perpendicular to its spine. These are equivalent to
the circles generated by this value for cylindrical surfaces. Such
lines would be generated by a plane stepping along the surface spine
by the given distance.
The first and third values are not significant.
Option RROPPA causes parametric hatch lines to be output, which correspond
to the locus of points of constant parameter value on the surface. The lines
may be output on faces with any type of underlying surface, though
longitudinal hatch lines on rolling ball blends ( i.e. lines of constant v
parameter ) are not supported.
If no option data is given, only those faces which have a hatching
attribute set will be hatched as specified by that attribute. If a
hatching specification is given in the option data, all faces will be
hatched according to that specification. Two values are required for the
option data: the first corresponds to the u parameter spacing, and
the second the spacing in v. Both values must be positive, and should lie
within the parameter range for the surface, which can be output using ENSUPA.
In both the RROPRH and RROPPA options the hatch lines generated are controlled
by two significant values for any given surface. If either value is zero hatch
lines are not generated for that case. If both values are non-zero the face is
cross hatched.
Option RROPUB is required if rendering is to take account of unfixed blending
surfaces; by default these are ignored. If RROPUB is specified with no option
data, unfixed blends will be rendered according to the attributes held in the
model; alternatively, option data can be used to specify how rendering is to
be done.
The edges of faces adjacent to the unfixed blend will be clipped to the blend
boundaries but hatch lines on such faces are not affected.
This option is ignored for general bodies, however - i.e. unfixed blends on
general bodies are not rendered.
Option RROPCT controls the representation of B-curves as polylines. A curved
edge is approximated by a number of straight lines called chords. The first
value in the option data is a chord tolerance. This is an upper bound on
the distance from each chord to the curve it is approximating. The second
value is a chord limit. This is an upper bound on the length of a chord
used in the approximation of a curved edge. The third value is an angular
tolerance. This limits the angular error between a curve and a chord used
in its approximation. This is an upper bound on the sum of the two angles
formed between the chord and the curve tangent at each chord end. If this
option is not specified a default angular tolerance is used.
If the option RROPVP is supplied then the system will attempt only to render
those bodies/faces which are inside or partly inside the viewport supplied.
The viewport is a cuboid region of model space and should be supplied in the
option data as a real list consisting of a centre, three axes, and lengths in
model units along these axes. The axes must be orthogonal but need not be
normalised.
While all faces that are inside or partly inside the viewport will be
rendered, no attempt is made to trim the output to the boundaries of the
viewport, and bodies or faces lying entirely outside, but close to it may be
rendered.
