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IDProjectCategoryView StatusDate SubmittedLast Update
0023942Community[OCCT] OCCT:Modeling Algorithmspublic2013-05-03 13:492019-12-17 13:49
ReporterRoman Lygin 
Assigned Tojgv 
PlatformAOSLOS VersionL
Product Version[OCCT] 6.6.0 
Target VersionFixed in Version 
Summary0023942: Modeling Algorithms - Pipe algorithms unrobust to number rounding
DescriptionThe GeomFill_Pipe algorithm produces very different results from essentially the same curve (before and after saving in a file).
Preliminary investigation (on 6.5.4 though) reveals that different laws (Law_BSpFunc or Law_Constant) get created depending on whether the curve is considered planar or not. The decision is made *directly* comparing floating point numbers (not with some epsilon tolerance).

However, regardless of the chosen law, the surface created from the curve prior to saving in a file is very distorted and constructed face has a redundant seam-edge.

A side note - the pipe algorithm often produces results with poles located very far from the path curve. This may mean that there are some computational sensitivities to input or interim data.
Steps To Reproduceinterpol c points.txt
tuya rc c 5
Dump of SweepApproximation
Error 3d = 34.823947825942
30 Segment(s) of degree 11
# note that actual data above can be different but the error is big anyway

mkface f rc
clear rc

# zoom to the bottom to see very distorted surface (around parameter 0)
# for example,
uiso u05 rc 0.5

# at the same time the derivative of the curve is OK
cvalue c 0. x y z d1x d1y d1z
line l x y z d1x d1y d1z

# save/restore and repeat - the surface can be less distorted
save c cc
restore cc
tuya rcc cc 5
TagsNo tags attached.
Test case numberbugs modalg_7 bug23942
Attached Filestxt file icon points.txt (215 bytes) 2013-05-03 13:49
png file icon screen2-660.png (27,136 bytes) 2013-05-03 13:49

- Relationships

-  Notes
mkv (tester)
2017-08-02 19:29

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

- Issue History
Date Modified Username Field Change
2013-05-03 13:49 Roman Lygin New Issue
2013-05-03 13:49 Roman Lygin Assigned To => jgv
2013-05-03 13:49 Roman Lygin File Added: points.txt
2013-05-03 13:49 Roman Lygin File Added: screen2-660.png
2017-08-02 19:29 mkv Test case number => bugs modalg_7 bug23942
2017-08-02 19:29 mkv Note Added: 0069076
2019-10-14 18:21 msv Relationship added related to 0026071
2019-12-17 13:49 kgv Summary Pipe algorithms unrobust to number rounding => Modeling Algorithms - Pipe algorithms unrobust to number rounding

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