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IDProjectCategoryView StatusLast Update
0022981CommunityOCCT:Modeling Algorithmspublic2013-04-29 15:24
ReporterTimo Assigned Toapn  
Status closedResolutionfixed 
PlatformWindowsOSVC++ 2010 
Product Version6.5.2 
Target Version6.6.0Fixed in Version6.6.0 
Summary0022981: BRepOffsetAPI_ThruSections fails to build a surface from closed wires
DescriptionIn order to reproduce the problem you can use the following Draw commands:

restore Turb1.brep t
explode t
thrusections r 0 0 t_1 t_2 t_3 t_4 t_5 t_6 t_7 t_8 t_9 t_10 t_11
thrusections r 0 0 t_1 t_2 t_3

If I leave out the first wire the exception is not thrown:
thrusections r 0 0 t_2 t_3 t_4 t_5 t_6 t_7 t_8 t_9 t_10 t_11

Tested with OCC 6.5.2

TKernel.dll!Standard_ConstructionError::Raise(const char * const AString) Zeile 12 + 0xcc Bytes C++
TKG3d.dll!Geom_BSplineSurface::InsertUKnots(const TColStd_Array1OfReal & Knots, const TColStd_Array1OfInteger & Mults, const double ParametricTolerance, const unsigned int Add) Zeile 1882 + 0xa Bytes C++
TKG3d.dll!Geom_BSplineSurface::Segment(const double U1, const double U2, const double V1, const double V2) Zeile 641 C++
TKOffset.dll!BRepOffsetAPI_ThruSections::CreateSmoothed() Zeile 642 C++
TKOffset.dll!BRepOffsetAPI_ThruSections::Build() Zeile 392 C++

Is it a bug or is there a problem with the wires / geometry?
Additional information
and documentation updates
Forum supervisor:
The posted problem has been checked and reproduced.
It looks like a bug. The commands:
>>thrusections r 0 0 t_1 t_2
>>thrusections r 0 0 t_2 t_3 t_4 t_5 t_6 t_7 t_8 t_9 t_10 t_11
are performed successfully, but together with the first section it leads to exception.
TagsNo tags attached.
Test case numberbugs modalg_5 bug22981

Attached Files

  • Turb1.brep (161,373 bytes)
  • thruSections with increased tolerance.PNG (19,759 bytes)


related to 0023436 closedjgv BRepOffsetAPI_ThruSections crashes when lofting through identical profiles 



2012-02-07 14:21


Turb1.brep (161,373 bytes)


2012-02-07 15:54

developer   ~0019439

BSplCLib::PrepareInsertKnots, which is called by Geom_BSplineSurface::InsertUKnots, returns false because (adeltaK2 > Tolerance).
adeltaK2: 1.3322676295501878e-015
Tolerance: 8.8817841970012523e-016

If the parametric tolerance (epsU) is increased to 8.8817841970012523e-015
before the call of InsertUKnots in Geom_BSplineSurface::Segment, the surface can be generated, but it doesn't seem to be OK in visualization (see "thruSections with increased tolerance.PNG").


2012-02-07 15:55


thruSections with increased tolerance.PNG (19,759 bytes)


2013-02-28 15:17

manager   ~0023527

The problem seems to be fixed by fix for 0023436, at least it is not reproduced on current master. I suggest the issue can be closed after adding a test case.


2013-03-12 17:03

administrator   ~0023681

Branch CR22981 was created from current state of master. The problem is fixed.
Test case - bugs/modalg_5/bug22981 - OK
Branch contains only test case and will be integrated.

Related Changesets

occt: master 972bd4bf

2013-03-12 13:02:56


Details Diff
0022981: BRepOffsetAPI_ThruSections fails to build a surface from closed wires

Added test case for issue 22981.
Affected Issues
add - tests/bugs/modalg_5/bug22981 Diff File

Issue History

Date Modified Username Field Change
2012-02-07 14:21 Timo New Issue
2012-02-07 14:21 Timo Assigned To => jgv
2012-02-07 14:21 Timo File Added: Turb1.brep
2012-02-07 15:54 Timo Note Added: 0019439
2012-02-07 15:55 Timo File Added: thruSections with increased tolerance.PNG
2013-02-28 15:16 abv Relationship added related to 0023436
2013-02-28 15:17 abv Note Added: 0023527
2013-02-28 15:17 abv Assigned To jgv => bugmaster
2013-02-28 15:17 abv Status new => feedback
2013-02-28 15:19 abv Target Version => 6.6.0
2013-02-28 17:57 bugmaster Assigned To bugmaster => mkv
2013-03-12 17:03 apn Note Added: 0023681
2013-03-12 17:04 apn Test case number => bugs modalg_5 bug22981
2013-03-12 17:04 apn Assigned To mkv => bugmaster
2013-03-12 17:04 apn Status feedback => tested
2013-03-18 20:48 apn Changeset attached => occt master 972bd4bf
2013-03-18 20:48 apn Assigned To bugmaster => apn
2013-03-18 20:48 apn Status tested => verified
2013-03-18 20:48 apn Resolution open => fixed
2013-04-23 13:35 aiv Status verified => closed
2013-04-29 15:24 aiv Fixed in Version => 6.6.0