Thickness - kill

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l3VGV
Posts: 36
Joined: Sat Oct 12, 2019 11:04 am

Thickness - kill

Postby l3VGV » Mon Feb 17, 2020 11:05 pm

More specifically. On both 0.19 and 0.18

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Russian/Russia (ru_RU)


OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.19510 (Git)
Build type: Release
Branch: master
Hash: c3eb6d9001c4d60ff7f7cae89f50bd3c965a9940
Python version: 3.7.3
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Russian/Russia (ru_RU)


a)

Applying Thickness(PartDesign or Part do not mater) will cause a crush, IF a part is made with splines. I was able to produce a reliable test case.

Image

That will crush right after clicking the button.


b)
Apllying thickness to Slot- loft, also crush. Ther is no splines, only lines and arcs.

this will crush
Image



But, if they do not rotated between each other, no too curved walls, then it works ok.
Image

if one of the slots is different size its ok too
Image


here is the files
0.18 only splines lofted
thicknesss018.FCStd
(13.02 KiB) Downloaded 7 times
0.19 splines and slots
thicknesss.FCStd
(187.48 KiB) Downloaded 7 times

***
Part two


One might think that this design will cause crush too? well, no. It will hide part initialy, but if you toggle "Make thickness inwards" few times and tune thickness value a bit, it works. And not only on flat faces, but on curved ones too! Very interesting.

Image

Image
learn curves.FCStd
(743.71 KiB) Downloaded 11 times

Crushing is totally not ok, but after some googling and reading i came to realization that may be opencascade issue. It known for crushing in case of curved geometry https://tracker.dev.opencascade.org/view.php?id=30003
Last edited by l3VGV on Wed Feb 19, 2020 4:52 am, edited 3 times in total.
User avatar
hammax
Posts: 1254
Joined: Thu Jan 19, 2017 5:03 pm
Location: Ammersee

Re: Thickness - kill

Postby hammax » Tue Feb 18, 2020 6:09 am

… I confirm (FC0.18.4 Win10-32)
Making these lofts with periodic BSpline - like you did - thickness leads to an immediate crash.
(Periodic BSpline has a flaw concerning its misplaced seed line)
But using normal BSpline with tangent constraints Thickness and 3D-Offset work normally.

Thickness_PBSpl.PNG
Thickness_PBSpl.PNG (23.35 KiB) Viewed 200 times
Attachments
thicknesss_0.18_2.FCStd
(54.85 KiB) Downloaded 5 times
l3VGV
Posts: 36
Joined: Sat Oct 12, 2019 11:04 am

Re: Thickness - kill

Postby l3VGV » Tue Feb 18, 2020 12:00 pm

I edited first post a litle bit. added one more test case what cause a crash but do not based on bsplines(lofted slots).

hammax wrote:
Tue Feb 18, 2020 6:09 am
But using normal BSpline with tangent constraints Thickness and 3D-Offset work normally.
Thank you! Now i have to learn how to live with that.