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IDProjectCategoryView StatusLast Update
0031961CommunityOCCT:Modeling Algorithmspublic2020-12-11 12:12
ReporterVladyslav Smorodskyi Assigned Tobugmaster  
PrioritynormalSeveritymajor 
Status closedResolutionno change required 
PlatformWindowsOSWindows 
Product Version7.5.0 
Summary0031961: Invalid bounding box produced for Face when triangulation is disabled
DescriptionBounding box calculation algorithm for faces produces wrong results when triangulation is turned off. Notice that in attached picture bounding box that uses triangulation is valid(Yellow), but one without triangulation is invalid(Blue).

Tested in OCCT 7.3.0 and 7.5.0
Steps To ReproduceUse attached file and execute next DRAW code

restore face.brep a
vdisplay a

bounding a -shape b1
vdisplay b1

bounding a -shape b2 -notriangulation
vdisplay b2

vfit
TagsNo tags attached.
Test case number

Attached Files

  • face.brep (11,806 bytes)
  • bbox_dump.png (4,998 bytes)

Activities

Vladyslav Smorodskyi

2020-11-25 16:05

reporter  

face.brep (11,806 bytes)

Vladyslav Smorodskyi

2020-11-25 16:05

reporter  

bbox_dump.png (4,998 bytes)

msv

2020-11-25 16:32

developer   ~0097074

It is not a bug.
Bounding box is not necessary close to the object. This box is computed on the poles of b-spline surface, in order to be computed very quick. If you want to compute the tight box then you need to use -optimal option.

Vladyslav Smorodskyi

2020-11-25 20:52

reporter   ~0097078

Thanks for pointing at optimal flag. At first glance BRepBndLib::Add seems same as BRepBndLib::AddOptimal, especially when triangulation is turned off, this adds a bit of confusion.

Issue can be closed.

Issue History

Date Modified Username Field Change
2020-11-25 16:05 Vladyslav Smorodskyi New Issue
2020-11-25 16:05 Vladyslav Smorodskyi Assigned To => msv
2020-11-25 16:05 Vladyslav Smorodskyi File Added: face.brep
2020-11-25 16:05 Vladyslav Smorodskyi File Added: bbox_dump.png
2020-11-25 16:32 msv Note Added: 0097074
2020-11-25 16:32 msv Assigned To msv => Vladyslav Smorodskyi
2020-11-25 16:32 msv Status new => feedback
2020-11-25 20:52 Vladyslav Smorodskyi Note Added: 0097078
2020-11-25 20:52 Vladyslav Smorodskyi Assigned To Vladyslav Smorodskyi => msv
2020-11-25 23:16 msv Assigned To msv => bugmaster
2020-11-25 23:16 msv Resolution open => no change required
2020-12-11 12:12 bugmaster Status feedback => closed