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IDProjectCategoryView StatusDate SubmittedLast Update
0030466Community[OCCT] OCCT:Modeling Algorithmspublic2019-01-31 17:342019-02-01 10:15
Reporteremei 
Assigned Tomsv 
PrioritynormalSeverityminor 
StatusnewResolutionopen 
PlatformWindowsOSVC++ 2015OS Version64 bit
Product Version[OCCT] 7.3.0 
Target VersionFixed in Version 
Summary0030466: Problems removing non-isolated holes
DescriptionNoticed when working on CADProcessor: concerns BRepAlgoAPI_Defeaturing

Problem when trying to remove a hole which is lying on more than 1 support face (the hole is at the intersection of multiple faces).

The algorithm fails to remove the hole.
Steps To Reproducerestore 2019-01-15_Intrados-HolesRemoved.brep a

explode a F
removefeatures result a a_19 a_20 a_25 a_26
Additional information
and documentation updates
From a preliminary study, the input looks OK (the feature faces and adjacent faces numbers are correct).
But the solid is not recreated properly, from BOPAlgo_MakerVolume::PerformInternal1, after BuildSolids call, only the bounding box is recreated, which leaves us with no result shape at the end.
TagsNo tags attached.
Test case number
Attached Files? file icon 2019-01-15_Intrados-HolesRemoved.brep (910,293 bytes) 2019-01-31 17:34
? file icon bug30466_extfaces.brep (166,251 bytes) 2019-02-01 10:15

- Relationships

-  Notes
(0081983)
emv (developer)
2019-02-01 10:15

The input shapes has a huge tolerance relatively the model size. Try the command 'tolsphere' in draw to see the tolerances of vertices:
tolsphere a


It is not safe to pass such arguments into the modeling operations.

But even after reducing the tolerances of the shape with the following commands:
settolerance a 1.e-7
fixshape a a

the algorithms fails to remove the hole.

It seems the reason is the huge tolerance obtained by the Face/Face intersection algorithm when intersecting the extended faces filling the hole. These tolerances do not allow producing the correct volume.
Here is the script to see these intersection tolerances:
restore bug30466_extfaces.brep c
explode c f

bopcurves c_2 c_3 -2d
# Tolerance Reached=0.53837672555709137

- Issue History
Date Modified Username Field Change
2019-01-31 17:34 emei New Issue
2019-01-31 17:34 emei Assigned To => msv
2019-01-31 17:34 emei File Added: 2019-01-15_Intrados-HolesRemoved.brep
2019-02-01 10:15 emv Note Added: 0081983
2019-02-01 10:15 emv File Added: bug30466_extfaces.brep


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