View Issue Details

IDProjectCategoryView StatusLast Update
0031849CommunityOCCT:Modeling Algorithmspublic2021-09-03 14:10
ReporterMatthias Assigned Tobugmaster  
PrioritynormalSeverityminor 
Status closedResolutionno change required 
PlatformWindowsOSVC++ 2015 
Product Version7.4.0 
Summary0031849: Modeling Algorithms - Boolean operations produce different results on different systems
DescriptionWe encountered slightly different results of geometry generation processes being performed on systems with different processor architecture (Ivy bridge vs. Skylake, Zen2 etc.).

Attached are our resulting breps produced by DRAW script below (res_skylake.brep and res_ivybridge.brep).

1) Can you confirm these different results?
2) Can you provide some details for this different behavior?
Steps To Reproduce
pload ALL
datadir c:/temp
restore s1.brep
restore s2.brep
bsection res s1 s2
save res res.brep
TagsNo tags attached.
Test case number

Attached Files

  • res_skylake.brep (211,232 bytes)
  • res_ivybridge.brep (211,242 bytes)
  • s1.brep (22,573 bytes)
  • s2.brep (44,272 bytes)
  • fds_ivybridge.brep (2,050,190 bytes)
  • fds_skylake.brep (2,005,540 bytes)

Activities

Matthias

2020-10-13 16:29

developer  

res_skylake.brep (211,232 bytes)

Matthias

2020-10-13 16:29

developer  

res_ivybridge.brep (211,242 bytes)

Matthias

2020-10-13 16:29

developer  

s1.brep (22,573 bytes)

Matthias

2020-10-13 16:29

developer  

s2.brep (44,272 bytes)

msv

2020-10-13 17:52

developer   ~0095941

The difference is not greater than in 11th digit in double precision values. I think it can be explained by different numeric processors on different platforms. It is hardly possible to fix this problem.

Matthias

2020-10-14 09:58

developer   ~0095952

You are right, but these differences increase with ongoing manipulations of the model.

We got aware of it when a (seemingly valid) shape produced on Ivybridge architecture could not be meshed on any platform using CADExchanger SDK (which is going to be investigated).

For the sake of completeness, the shapes are attached (fds_ivybridge.brep, fds_skylake.brep).

Matthias

2020-10-14 09:59

developer  

fds_ivybridge.brep (2,050,190 bytes)

Matthias

2020-10-14 09:59

developer  

fds_skylake.brep (2,005,540 bytes)

msv

2020-10-14 10:58

developer   ~0095955

Both shapes are meshed with no problems using OCCT BRepMesh algorithm.

msv

2021-08-29 19:00

developer   ~0103515

Dear Matthias, could you provide some feedback on this bug?

Matthias

2021-08-30 10:14

developer   ~0103524

Dear msv,

cadex confirmed a bug in their visualization mesher causing the failing meshing of the slightly different shape.

Issue could be closed, the information shared here is sufficient (at least for myself).

msv

2021-08-30 10:29

developer   ~0103525

Please close this bug.

Issue History

Date Modified Username Field Change
2020-10-13 16:29 Matthias New Issue
2020-10-13 16:29 Matthias Assigned To => bugmaster
2020-10-13 16:29 Matthias File Added: res_skylake.brep
2020-10-13 16:29 Matthias File Added: res_ivybridge.brep
2020-10-13 16:29 Matthias File Added: s1.brep
2020-10-13 16:29 Matthias File Added: s2.brep
2020-10-13 17:02 kgv Assigned To bugmaster => msv
2020-10-13 17:02 kgv Summary Boolean operations produce different results on different systems => Modeling Algorithms - Boolean operations produce different results on different systems
2020-10-13 17:02 kgv Steps to Reproduce Updated
2020-10-13 17:52 msv Note Added: 0095941
2020-10-14 09:58 Matthias Note Added: 0095952
2020-10-14 09:59 Matthias File Added: fds_ivybridge.brep
2020-10-14 09:59 Matthias File Added: fds_skylake.brep
2020-10-14 10:58 msv Note Added: 0095955
2021-08-29 19:00 msv Note Added: 0103515
2021-08-29 19:00 msv Assigned To msv => Matthias
2021-08-29 19:00 msv Status new => feedback
2021-08-29 19:00 msv Target Version 7.6.0 => 7.7.0
2021-08-30 10:14 Matthias Note Added: 0103524
2021-08-30 10:14 Matthias Assigned To Matthias => msv
2021-08-30 10:29 msv Note Added: 0103525
2021-08-30 10:29 msv Assigned To msv => bugmaster
2021-08-30 10:29 msv Resolution open => no change required
2021-08-30 10:29 msv Target Version 7.7.0 =>
2021-09-03 14:10 bugmaster Status feedback => closed