[Problem] PartDesign: Taper function error (in OCC)

[FlubM]

Is there an existing issue for this?

• I have searched the existing issues

Forums discussion

http://forum.freecadweb.org:80/viewtopic.php?f=13&t=75281

Version

0.20 (Release)

Full version info

[code]
OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.2.29177 +426 (Git)
Build type: Release
Branch: (HEAD detached from 0.20.2)
Hash: 930dd9a76203a3260b1e6256c70c1c3cad8c5cb8
Python 3.8.10, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.6.3
Locale: German/Switzerland (de_CH)
[/code]

Subproject(s) affected?

PartDesign

Issue description

The taper function has an error.
Depending on where the hole is, the taper jumps from negative to positive.
If you move the large hole to the left, the taper changes from positive to negative
It seems to be a bug in the FC software

Anything else?

TaperError.zip

Code of Conduct

• I agree to follow this project's Code of Conduct

[adrianinsaval]

confirmed, maybe it's a bug when offsetting circles or when detecting if they are inside other profiles. Other shapes besides circles seem to work fine, even constructing a circle using two arcs works correctly

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.21.0.31850 (Git)
Build type: Release
Branch: master
Hash: d8d3bb8
Python 3.10.9, Qt 5.15.6, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3
Locale: C/Default (C) [ OS: Spanish/Paraguay (es_PY) ]
Installed mods:

@donovaly any clues? IIRC we had some workarounds when offsetting circles due to a bug in occt, perhaps this bug is no longer present and the workaround is making things worse now?

[donovaly]

This is a long-standing bug in OCC. I don't see how we could fix this. Here the 3 different outputs of OCC when you move only the upper point slightly:

[luzpaz]

@donovaly is this a dupe of an open bug we have already ?

[donovaly]

@donovaly is this a dupe of an open bug we have already ?

Not that I know but i am not good at searching.

[tbMaker1]

There is a discrepency on taper angles between single edge and multi-edge inner sketches. I made a PR to solve it and to enable to set inward/outward tapers either parallel or opposite.
I'll have a look at your issue too. When I toggle my checkbox, it toggles the taper on your shape.