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IDProjectCategoryView StatusLast Update
0025856CommunityOCCT:Modeling Algorithmspublic2021-08-29 18:51
ReporterMarkus Assigned Tomsv  
Status newResolutionopen 
Product Version6.8.0 
Target Version7.7.0 
Summary0025856: BRepOffsetAPI_ThruSections returns an invalid shape if one wire contains degenerated edges
DescriptionWhen a wire contains degenerated edges and a normal edge and it is used as input to ThruSections algorithm, the results are:

If only one additional "normal" wire is used, the result is invalid, namely it is considered “Not connected” by checkshape.

If two additional "normal" wires are used, the result is invalid, but there is a different problem: InvalidSameParameter flag.

Both problems can be fixed by fixshape.

Steps To Reproducerestore threeWires.brep t
explode t
thrusections -N r 0 0 t_1 t_2
checkshape r
fixshape rr r
checkshape rr

restore threeWires.brep t
explode t
thrusections -N r 0 0 t_1 t_2 t_3
checkshape r
fixshape rr r
checkshape rr
TagsNo tags attached.
Test case numberbugs modalg_7 bug25856_1, bug25856_2

Attached Files

  • threeWires.brep (10,925 bytes)


related to 0022021 assignedjgv Exception during a loft building between two closed contours 
related to 0027568 closedbugmaster Exception is thrown when a degenerated edge is added to a wire 



2015-02-24 15:45


threeWires.brep (10,925 bytes)


2015-02-24 17:58

developer   ~0037833

Last edited: 2015-02-24 17:59

The input argument t_1 is invalid shape, as it contains degenerated edges with no pcurve. A degenerated edge is used to designate a particular point on a surface. In this case there is no surface on input, so there is no justification to create degenerated edge in the input.
Now ThruSection cannot correctly treat the situation when it is needed to create a patch face between a vertex of one section and an edge of another section. It is a point to improve the algorithm.


2017-08-08 17:40

tester   ~0069219

Problem described in issue is reproduced on current state of OCCT.

Issue History

Date Modified Username Field Change
2015-02-24 15:45 Timo New Issue
2015-02-24 15:45 Timo Assigned To => msv
2015-02-24 15:45 Timo File Added: threeWires.brep
2015-02-24 17:58 msv Note Added: 0037833
2015-02-24 17:59 msv Note Edited: 0037833
2015-04-09 12:56 msv Severity minor => feature
2015-04-09 12:56 msv Target Version 6.9.0 => 7.1.0
2016-06-13 14:25 Timo Relationship added related to 0027568
2016-07-06 19:27 msv Relationship added related to 0022021
2016-10-28 17:03 msv Target Version 7.1.0 => 7.2.0
2017-05-31 15:39 Timo Reporter Timo => Markus
2017-07-21 11:16 msv Target Version 7.2.0 => 7.3.0
2017-08-08 17:40 mkv Test case number => bugs modalg_7 bug25856
2017-08-08 17:40 mkv Note Added: 0069219
2017-08-08 17:52 mkv Test case number bugs modalg_7 bug25856 => bugs modalg_7 bug25856_1, bug25856_2
2017-12-05 17:01 msv Target Version 7.3.0 => 7.4.0
2019-08-12 16:43 msv Target Version 7.4.0 => 7.5.0
2020-09-14 22:56 msv Target Version 7.5.0 => 7.6.0
2021-08-29 18:51 msv Target Version 7.6.0 => 7.7.0