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IDProjectCategoryView StatusLast Update
0031453CommunityOCCT:Modeling Algorithmspublic2021-08-29 19:24
Reporterblobfish Assigned Toszy  
PrioritynormalSeverityminor 
Status newResolutionopen 
PlatformLinuxOSDebian 
Product Version7.4.0 
Target Version7.7.0 
Summary0031453: Modeling Algorithms - simple chamfer smashes vertex tolerance
Descriptionchamfering a box causes the new vertices to have a much looser tolerance than expected. A simple blend in the same condition keeps Precision::Confusion.
Steps To Reproduce
pload MODELING
box b 20 20 20
explode b E
chamf c b b_1 1.0
maxtolerance c


output:
## Tolerances on the shape c  (nbFaces:7  nbEdges:15 nbVtx:10)

    Face   : Min 1.00000e-07    Max  1.00000e-07 
 
    Edge   : Min 1.00000e-07    Max  1.00000e-07 
 
    Vertex : Min 1.00000e-07    Max  1.00000e-04 
Additional information
and documentation updates
occt 7.4, actually 8bfae263c1
I have not tested with an older version, but I believe this is a regression as I haven't noticed this behavior before.
TagsNo tags attached.
Test case number

Activities

msv

2020-03-20 21:10

developer   ~0091096

We should check if it is a regression.

blobfish

2021-04-01 14:15

reporter   ~0099946

Problem:
  tolreached is never set for plane to plane intersection. So the edge
  tolerance is set to the 'loose' input tolerance and vertex tolerances
  are established from the edge. Interestingly, the edge tolerance
  gets fixed in a later 'SameParameter' operation and we are just
  left with the 'loose' vertex tolerances.

I was able to fix this by inserting:
  'tolreached = Min(tolreached,ChFi3d_EvalTolReached(S1,Pc1,S2,Pc2,C3d));'
to:
  src/ChFi3d/ChFi3d_Builder_0.cxx:3183

comments:
  That function call is probably overkill in a 'plane to plane'
  intersection, but it was the least intrusive change I could come up,
  short of just assigning precision::confusion. This appears to fix
  the problem, but I have NOT done any regression tests. I looked into
  using tolr1 and tolr2, but they are never updated by
  ProjLib_ProjectedCurve in the planar case.
    ChFi3d_Builder_0.cxx:3180 to:
    ChFi3d_Builder_0.cxx:1185 to:
    src/ProjLib/ProjLib_ProjectedCurve.cxx:419

Issue History

Date Modified Username Field Change
2020-03-20 19:02 blobfish New Issue
2020-03-20 19:02 blobfish Assigned To => msv
2020-03-20 21:10 msv Assigned To msv => szy
2020-03-20 21:10 msv Note Added: 0091096
2021-04-01 14:15 blobfish Note Added: 0099946
2021-04-01 14:26 kgv Product Version => 7.5.0
2021-04-01 14:26 kgv Target Version => 7.6.0
2021-04-01 14:26 kgv Summary simple chamfer smashes vertex tolerance => Modeling Algorithms - simple chamfer smashes vertex tolerance
2021-04-01 14:26 kgv Steps to Reproduce Updated
2021-04-01 14:26 kgv Product Version 7.5.0 => 7.4.0
2021-08-29 19:24 msv Target Version 7.6.0 => 7.7.0