[BUG] BRepOffsetAPI_ThruSections fails to build a surface from closed wires

In 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?

Kind regards,

Forum supervisor's picture

Dear Timo,
I would like to inform you that 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.
I suggest you to make a contribution and register the issue in Mantis Bugtracker,
which is available via the Collaborative portal - http://dev.opencascade.org/index.php?q=home/get_involved.

Timo Roth's picture

The bug is now registered with ID 22981.