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0022618Open CASCADE[OCCT] OCCT:Visualizationpublic2011-06-21 22:032019-09-04 12:08
san 
san 
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[OCCT] 7.5.0* 
0022618: Visualization - Tool for building generic wireframe representation of a face
The problem of building a wireframe representation (a set of polylines for the
face' edges and isolines) of a topological face is not new at all.

1. Currently, there are several similar classes in OCCT in StdPrs and Prs3d
packages.
The complete set of such classes is to be identified and listed in this bug. One
more similar tool can be found in SALOME GEOM module.

AIS_Shape class currently use StdPrs_WFDeflectionRestrictedFace class (through
Prs3d_WFShape) for this purpose. But this class does not build a generic
wireframe mesh containing points and polylines. Instead, it fills
Prs3d_Presentation with internal OCCT data. Thus it is extremely difficult to
reuse this class outside OCCT 3D viewer.

SALOME GEOM module uses OCC2VTK_WireframeFace class to build wireframe
representation for VTK viewer. This class uses slightly different (at the first
glance) implementation of isoline building algorithm. It is not generic, either,
as it fills VTK data structures.

Meanwhile, sometimes it is necessary to have wireframe representation in the
form of generic polylines, to pass it to some third-party 3D engine or just to
avoid dependency on SALOME.
Today the most straightforward solution is copy/paste-based...

2. The idea is to compare the existing implementations and create a generic tool
somewhere, presumably at the level of BRepMesh package.
The name of such a tool is to be discussed (I suggest something like
BRepMesh_IsoBuilder).
This tool should fill generic data structures, such as a list of Poly_Polygon3D
containers.

In case if Poly_Triangulation is available for the underlying face, it looks
very interesting to analyze the possibility of building the polylines on the
triangulation and creating Poly_PolygonOnTriangulation containers instead, so as
to use exactly the same discrete geometry as for shaded face representation,
that would minimize visual artifacts when wireframe and shaded representations
are combined in a 3D scene. However, such optimization is to be analyzed
carefully.

3. Finally, AIS_Shape should be migrated to this new tool, and obsolete StdPrs
and Prs3d classes should be removed. The same procedure could be also applied to
OCC2VTK_WireframeFace if necessary.
No tags attached.
related to 0023519closed bugmaster Community Mixing wireframe and shaded visualization impacts performance 
related to 0022877closed bugmaster Open CASCADE Draw Harness - add plugin for VIS component 
related to 0025300closed ski Open CASCADE Visualization - Build wireframe representation consistent with the shape's triangulation 
related to 0027596closed bugmaster Open CASCADE Visualization, StdPrs_WFShape - pack isolines into single group of primitives 
related to 0030599assigned tizmaylo Open CASCADE Visualization - implement StdPrs_SectionLines tool 
related to 0023984closed bugmaster Open CASCADE Incorrect visualization of wires in wireframe mode 
Issue History
2011-08-02 11:24bugmasterCategoryOCCT:VIZ => OCCT:Visualization
2011-10-03 14:39pdnFixed in VersionEMPTY =>
2011-10-03 14:39pdnTarget Version => 6.5.3
2011-10-03 14:39pdnDescription Updatedbug_revision_view_page.php?rev_id=664#r664
2012-03-22 06:38abvTarget Version6.5.3 => 6.5.4
2012-03-29 16:51sanNote Added: 0020202
2012-10-20 10:15abvNote Added: 0021866
2012-10-20 10:15abvAssigned Tobugmaster => san
2012-10-20 10:15abvStatusnew => feedback
2012-10-20 10:20abvTarget Version6.5.4 => Unscheduled
2012-10-27 03:50sanDescription Updatedbug_revision_view_page.php?rev_id=4437#r4437
2012-10-27 03:51sanNote Deleted: 0020202
2012-10-27 03:52sanStatusfeedback => assigned
2012-10-27 03:53sanAssigned Tosan => abv
2012-10-27 03:53sanStatusassigned => feedback
2012-10-29 08:48abvNote Deleted: 0021866
2012-10-29 09:12abvAssigned Toabv => san
2012-10-29 09:12abvStatusfeedback => assigned
2012-11-15 20:36sanRelationship addedrelated to 0023519
2014-02-13 11:20kgvPrioritynormal => low
2014-02-13 11:21kgvRelationship addedrelated to 0022877
2014-02-17 15:24kgvProduct Version => 7.0.0
2014-02-17 15:24kgvProduct Version7.0.0 =>
2014-02-17 15:24kgvTarget VersionUnscheduled => 7.0.0
2014-02-17 16:26kgvRelationship addedrelated to 0023984
2014-09-29 22:36kgvTarget Version7.0.0 => 7.1.0
2014-09-30 19:44sanRelationship addedrelated to 0025300
2016-06-16 20:47kgvRelationship addedrelated to 0027596
2016-10-25 09:38kgvTarget Version7.1.0 => 7.2.0
2017-07-20 10:52kgvTarget Version7.2.0 => 7.4.0
2019-05-07 11:44kgvRelationship addedrelated to 0030599
2019-08-13 12:04kgvTarget Version7.4.0 => 7.5.0*
2019-09-04 12:08kgvSummaryTool for building generic wireframe representation of a face => Visualization - Tool for building generic wireframe representation of a face

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