Ticket #2187 - Unusable Wire from Section

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Chris_G
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Re: Unusable Wire from Section

Postby Chris_G » Sat Jan 28, 2017 9:58 pm

IMHO, but I am not a developer, this bug is valid.
The user doesn't even have an hint on what went wrong.
The user should, at least, be informed that the path is not valid for this sweep.
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Kunda1
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Re: Unusable Wire from Section

Postby Kunda1 » Tue Mar 14, 2017 11:44 am

DeepSOIC wrote:This is why I created Macro Section some while ago.
Do you mind fleshing out what part of issue #2187 is a legit bug?
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Re: Unusable Wire from Section

Postby Kunda1 » Tue Jul 18, 2017 11:24 pm

bump
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Re: Unusable Wire from Section

Postby Kunda1 » Wed Aug 23, 2017 11:57 am

Bump
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Re: Unusable Wire from Section

Postby Kunda1 » Thu Dec 07, 2017 11:54 am

ickby wrote:ping
please weigh in once more to clarify
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Re: Unusable Wire from Section

Postby Chris_G » Thu Dec 07, 2017 1:48 pm

I am a bit sceptical about the result of the Part.Section tool.
From what I see here : FeaturePartSection.cpp#L45, it uses OCC's BRepAlgoAPI_Section that inherits from BRepAlgoAPI_BooleanOperation.
However, the intersection curves are not similar between a section operation and, for example, a cut operation.
See the result for the 2 shapes of this example.
The 2 input shapes :
section-1.jpg
section-1.jpg (14.92 KiB) Viewed 799 times
The section operation gives the following result (the red edges):
Edge 1 : BSpline curve, Degree 1, 965 poles, continuity C0
Edge 2 : BSpline curve, Degree 1, 430 poles, continuity C0
section-2.jpg
section-2.jpg (16.19 KiB) Viewed 799 times
The cut operation gives the following result on these same edges:
Edge 1 : BSpline curve, Degree 8, 170 poles, continuity C1
Edge 2 : BSpline curve, Degree 8, 79 poles, continuity C1
section-3.jpg
section-3.jpg (23.46 KiB) Viewed 799 times
Why such a difference ?
Would there be a way to make the Section tool produce the same kind of intersection curves as the other Boolean Operations ?
Werner ?
wmayer wrote: ping
UR_
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Re: Unusable Wire from Section

Postby UR_ » Wed Dec 13, 2017 10:37 pm

Please have a look at this section implementation by DeepSOIC

https://www.freecadweb.org/wiki/Macro_Section

Example SectionPart vs FCMacro.png
Example SectionPart vs FCMacro.png (46.11 KiB) Viewed 750 times
Section by Macro.png
Section by Macro.png (11.16 KiB) Viewed 750 times
Section by PartWB.png
Section by PartWB.png (10.19 KiB) Viewed 750 times

File:
SectionPart vs FCMacro.FCStd
(68.3 KiB) Downloaded 23 times


Done with:
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.12802 (Git)
Build type: Release
Branch: master
Hash: 91bb7ed0c51ba47f011199af7bc0a3a2964cf5be
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.1.0
Locale: German/Germany (de_DE)
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Chris_G
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Re: Unusable Wire from Section

Postby Chris_G » Thu Dec 14, 2017 8:35 pm

UR_ wrote:
Wed Dec 13, 2017 10:37 pm
Please have a look at this section implementation by DeepSOIC
Hi UR_,
I knew DeepSOIC's macro.
My question was more : "Why does OCC have this strange behaviour ?"
Even if I suppose that we probably cannot do anything anyway :(
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Kunda1
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Re: Unusable Wire from Section

Postby Kunda1 » Sat Mar 03, 2018 10:44 am

soft bump to keep this discussion going
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Re: Unusable Wire from Section

Postby Kunda1 » Sat Jun 09, 2018 1:24 pm

Should we open an upstream ticket about this ?
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