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0022869Community[OCCT] OCCT:Shape Healingpublic2011-12-20 16:122019-09-04 13:04
szy 
gka 
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assignedopen 
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[OCCT] 6.5.2 
[OCCT] 7.5.0* 
bugs heal bug22869
0022869: Error during triangulation
Post from the Forum (Francesco Argese ) - http://www.opencascade.org/org/forum/thread_22423/. [^]

"Hi all,

I'm having some problems loading a model taken from grabcad. It is a spring [1] and if I try to load it with OpenCascade Import/Export example (version 6.5.2) it seems to have some problems.

Among attachments the results with Import/Export that lack something. If I load it with an app written by me using OpenCascade I have the same problem and 4 faces give me null triangulation. I have the same problem with other models, too. The model Springs.igs is the smallest that give me this problem.

What could be the problem? Any suggestions? Is there any parameter that i can set in the igs reader to resolve?

Thanks in advance.
Francesco Argese

[1] http://grabcad.com/library/springs [^]
Attached file: Springs_OCCT_Import_Export.jpg (172 980 bytes)"

Draw command incmesh returns error status:
==> Meshing statuses: SelfIntersectingWire
pload ALL
igesread Spring.igs s *
checkshape s ## Ok
incmesh s 0.01
## Meshing statuses: SelfIntersectingWire
No tags attached.
? Spring.igs (214,512) 2011-12-20 16:12
https://tracker.dev.opencascade.org/
png spring_face_1.png (39,692) 2013-03-11 10:29
https://tracker.dev.opencascade.org/
png spring_face_1_part_2d.png (8,088) 2013-03-11 10:29
https://tracker.dev.opencascade.org/
Issue History
2011-12-20 16:12szyNew Issue
2011-12-20 16:12szyAssigned To => jgv
2011-12-20 16:12szyFile Added: Spring.igs
2011-12-20 16:12szyAssigned Tojgv => msv
2011-12-20 16:16abvAssigned Tomsv => pdn
2011-12-20 16:16abvStatusnew => assigned
2012-01-12 09:54abvNote Added: 0019096
2012-03-21 14:21abvTarget Version6.5.3 => 6.5.4
2012-10-23 18:41abvTarget Version6.5.4 => 6.6.0
2012-11-09 10:50abvCategoryOCCT:Modeling Algorithms => OCCT:Mesh
2013-03-01 21:35abvAssigned Topdn => oan
2013-03-01 21:35abvTarget Version6.6.0 => 6.7.0
2013-03-11 10:28oanNote Added: 0023637
2013-03-11 10:29oanNote Edited: 0023637bug_revision_view_page.php?bugnote_id=23637#r5140
2013-03-11 10:29oanFile Added: spring_face_1.png
2013-03-11 10:29oanFile Added: spring_face_1_part_2d.png
2013-03-11 10:29oanCategoryOCCT:Mesh => OCCT:Modeling Algorithms
2013-03-11 10:30oanAssigned Tooan => jgv
2013-03-11 10:31oanCategoryOCCT:Modeling Algorithms => OCCT:Shape Healing
2013-03-11 10:31oanNote Edited: 0023637bug_revision_view_page.php?bugnote_id=23637#r5141
2013-03-11 10:35oanAssigned Tojgv => gka
2013-12-21 10:21abvTarget Version6.7.0 => 6.7.1
2014-04-04 18:19abvTarget Version6.7.1 => 6.8.0
2014-09-26 09:51abvTarget Version6.8.0 => 7.1.0
2016-10-26 12:20gkaTarget Version7.1.0 => 7.2.0
2017-07-27 09:33abvTarget Version7.2.0 => 7.4.0
2017-10-17 16:13apvTest case number => bugs heal bug22869
2017-10-17 16:13apvNote Added: 0071576
2019-09-04 13:04abvTarget Version7.4.0 => 7.5.0*

Notes
(0019096)
abv   
2012-01-12 09:54   
The same problem is reproduced on previous versions of OCCT (checked 6.3.0 and 6.5.0)
(0023637)
oan   
2013-03-11 10:28   
(edited on: 2013-03-11 10:31)
This bug is not a problem of the BRepMesh, but the fixshape functionality.

incmesh and checkshape commands indicate self-intersetion problem, so, the BRepMesh performs check, finds problems and breaks further calculations that is correct behavior (see also the attacked screenshots).
The checkshape prints the following log:


------------------------------------------------------


--- BRepCheck Wire: AutoIntersection Phase1 -> Erreur

--- BRepCheck Wire: AutoIntersection Phase2 -> Bon
--- distance Point Vertex : 2.70142 (tol 0.007878383)
--- Erreur Max sur E1 : 0.07563974 Tol_Edge:0.08069114
--- Erreur Max sur E2 : 0.07316676 Tol_Edge:0.07431163

------------------------------------------------------


--- BRepCheck Wire: AutoIntersection Phase1 -> Erreur

--- BRepCheck Wire: AutoIntersection Phase2 -> Bon
--- distance Point Vertex : 0.1020595 (tol 0.007878383)
--- Erreur Max sur E1 : 9.060006e-005 Tol_Edge:0.08069114
--- Erreur Max sur E2 : 0.0001042605 Tol_Edge:0.07431163

------------------------------------------------------


--- BRepCheck Wire: AutoIntersection Phase1 -> Erreur

--- BRepCheck Wire: AutoIntersection Phase2 -> Bon
--- distance Point Vertex : 2.697098 (tol 0.007878383)
--- Erreur Max sur E1 : 0.07713977 Tol_Edge:0.08069114
--- Erreur Max sur E2 : 0.07293055 Tol_Edge:0.07412683

------------------------------------------------------


--- BRepCheck Wire: AutoIntersection Phase1 -> Erreur

--- BRepCheck Wire: AutoIntersection Phase2 -> Bon
--- distance Point Vertex : 2.52925 (tol 0.006648691)
--- Erreur Max sur E1 : 0.05162059 Tol_Edge:0.05658045
--- Erreur Max sur E2 : 0.04573681 Tol_Edge:0.07412683
This shape seems to be valid


At the same time, the fixshape command doesn't process this problem and leaves it without any changes.

I move this bug to the Shape Healing category.

(0071576)
apv   
2017-10-17 16:13   
Problem described in issue is reproduced on current state of OCCT.