Boolean operations on bodies not working

[wormball]

Hello!

When i try to perform partdesign boolean operation on bodies, it either crashes immediately, or freezes and consumes all the available memory, or ends the operation successfully, but the result is completely invisible regardless of any space key depressions at the model tree. Moreover, when i try to do something with the result, e. g. edit some sketch or even save and load the file again, it either crashes immediately, or freezes and consumes all the available memory so i have to kill it manually. It happens every time i try partdesign boolean, whether it is any other file, freecad 0.19 and/or under windows 10.

Is this the intended behavior? If yes, why the manual says it does something else? https://wiki.freecadweb.org/PartDesign_Boolean If not, is there a way to make it work like the manual says?

Thanks in advance.

P. S. Also your forum freezes drastically (on 4/8 core xeon!) and shuffles attachment comments.

OS: Ubuntu 18.04.4 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4.
Build type: Release
Python version: 3.6.8
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Russian/Russia (ru_RU)

[Bance]

Works OK for me....

Bool.jpeg (41.46 KiB) Viewed 1279 times

OS: Linux Mint 18.2 Sonya (X-Cinnamon/cinnamon)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Python version: 3.5.2
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)

[chrisb]

Version: 0.18.4.

Please don't post any errors based on 0.18 only. Check if the error exists in 0.19 (as well).

[wormball]

I have installed freecad-daily.

OS: Ubuntu 18.04.4 LTS (GNOME-Flashback:GNOME:/gnome-flashback-metacity)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Russian/Russia (ru_RU)

Now it performs the desired operation (maybe 0.19 changed since i last tried it) but the result looks slightly odd when semi-transparent.

However i have found a workaround: https://youtu.be/lb-oPWEUQ30?t=1070 . So you choose part workbench, click "boolean", choose part design again and click "body". And all is fine and looking nice.

[chrisb]

It looks as if you have two objects visible at the same time which occupy the same space. This leads to the so called Z-fighting.

[wormball]

I hit space on every tree entry, but it did not help.

[chrisb]

I can confirm the Z-fighting issue. It is a regression, possibly introduced by the Big Merge?

It was already present in this version from shortly after the big merge:

OS: macOS High Sierra (10.13)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.17798 (Git)
Build type: Release
Branch: master
Hash: 7e60631239109c632a8f6cca83f6e7e5502e43a1
Python version: 3.7.3
Qt version: 5.9.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/Germany (en_DE)

It was not present in this version from shortly before the big merge:

OS: macOS High Sierra (10.13)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.17681 (Git)
Build type: Release
Branch: master
Hash: e94af7ff5e873f263cac51d7d47df68eca183250
Python version: 3.7.3
Qt version: 5.9.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/Germany (en_DE)

ping

ping

[realthunder]

I can confirm the Z-fighting issue. It is a regression, possibly introduced by the Big Merge?

No, this is caused by the recent change of default Lighting. Change it to double-side rendering can fix the problem.

lighting.gif (371.93 KiB) Viewed 1186 times

ping

Maybe auto change to double-side rendering when there is transparency?

[chrisb]

Maybe auto change to double-side rendering when there is transparency?

Sounds reasonable.

[wmayer]

When i try to perform partdesign boolean operation on bodies, it either crashes immediately, or freezes and consumes all the available memory

You should check the user settings under Edit > Preferences > Part design > Shape view for Maximum deviation from the model bounding box. By default this value is set to 0.5 % which is a good compromise between meshing speed/RAM usage and appearance quality. If you set it to a very low value you get a nicer rendering result but the meshing can require much more time and the RAM usage increases, too.

I can confirm the Z-fighting issue. It is a regression, possibly introduced by the Big Merge?

In this context it's helpful to understand that when transparencies are used in a model there is no guarantee that everything works perfectly in all cases:
SoGLRenderAction::TransparencyType

Many years ago we used the option SORTED_OBJECT_BLEND in FreeCAD but switched to SORTED_OBJECT_SORTED_TRIANGLE_BLEND a few years ago which fixed some rendering artifacts.

But still you can easily run into unexpected behaviour. There is/was a bug in Mantis where depending on the view position an object was incorrectly rendered opaque and transparent for other view positions.

No, this is caused by the recent change of default Lighting. Change it to double-side rendering can fix the problem.

For the others: In v0.19 a new option in the preferences was added to set the lighting mode for Part objects (One-side or Two-side rendering). In the past you could change this only in the property editor for each object manually but there was no global option. The default was Two-side rendering but this option is not unproblematic because it hides possible problems in your model. If faces have inconsistent orientations then e.g. this can lead to problems for boolean operations. That's why I decided to set to default to One-side rendering when adding this user setting.

The downside is that when transparencies are used you get the Z-fighting issue. I don't mind to restore the old default value, i.e. to set Two-side rendering but you must be aware of that it's not obvious and easy to see if your model suffers from broken orientations.
Furthermore as soon as you hover over a face or select it the Z-fighting issue is back -- independent if One-side or Two-side rendering is used.

Maybe auto change to double-side rendering when there is transparency?

I am no friend of too many automatisms where it's not clear if the behaviour is the same on all platforms. Then it's easier to set again Two-side rendering as default but leave the user the possibility to change the settings.