[FreeCAD 0.19.22411, Win10] Access Violation when trying to create a fillet

[foosel]

Hi there

New FreeCAD user here, currently running through various CAD challenges to get up to speed. Seeing a highly annoying Access Violation here and there that seems to be connected with fillets and that renders the UI unusable and requires a restart of FreeCAD to get back in business.

File with which to reproduce and log are attached. I can reproduce this reliably by trying to add any fillet to the area indicated in the attached screenshot on the "Phase 2" body:

freecad_2020-09-20_17-13-18.png (54.12 KiB) Viewed 1773 times

I am aware that this is probably caused by me still doing something wrong in my modelling, but as it causes the UI to do nothing but log endless Access Violation lines to the report console ("17:22:41 Unhandled Base::Exception caught in GUIApplication::notify. The error message is: Access violation") I figured I should still report it. Happy to answer any questions or collect more data.

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22411 (Git)
Build type: Release
Branch: master
Hash: d4519d5aec15bc08f029da5ed15410a494b57b2c
Python version: 3.8.5
Qt version: 5.12.6
Coin version: 4.0.0
OCC version: 7.4.0
Locale: German/Germany (de_DE)

[Vincent B]

Freecad still tricky with fillets.
Need to looking for a lot of combinations to find the good solution for their good order.
I've move the sketch005 to avoid a edge.
here file link: https://mon-partage.fr/f/l4WgIe8n/

[vocx]

I am aware that this is probably caused by me still doing something wrong in my modelling, ...

I see no error messages in my system, but indeed if you try to create a fillet it's not possible. Whenever you have issues, use Part_CheckGeometry to check the validity of your shapes. You can test each feature one by one until you find the problem.

freecad_2020-09-20_17-13-18_colinear_edges.png (21.23 KiB) Viewed 1745 times

A problem is the edges that are created in the solid when you perform the groove. These types of coplanar faces or colinear edges often cause problems with further boolean operations (blame OpenCASCADE). You can choose the groove and refine it with the option in the property editor. Then the solid is no longer invalid and you can proceed with more dressup features.

Code: Select all

OS: Ubuntu 18.04.5 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22465 (Git)
Build type: Debug
Branch: master
Hash: a028ea94ccdc0c024c73e6d583fcf11b2c039d46
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

[foosel]

Thank you! I figured it has something to do with that as I've had problems with that in other CAD packages as well. Will take a look at all those links and recommendations, highly appreciated!

Still not ideal to have to restart to get the tool back in usable shape. While that Access Violation gets logged endlessly I can do pretty much nothing but save and exit. Getting an error message as in other cases with invalid geometry would certainly be more helpful here, even it's just "oops something went wrong here". In short, a more graceful handling of some error condition night be needed here. Will try to spin up a linux vm tomorrow and test a nightly as it's apparently not generally reproducing.

[Olav]

We have a real open source and 3D-printing celebrity here! Thank you, foosel, for creating OctoPrint. I use it regularly.

Will try to spin up a linux vm tomorrow and test a nightly as it's apparently not generally reproducing.

I just tried making the same model from the Model Mania collection in up-to-date FreeCAD 0.19 on (X)ubuntu 18.04 and while it doesn't crash, it does give the rather terse messages of "Failed to create fillet" and "Resulting shape is invalid" a lot. It will fillet some of the edges but when I try to add some more it will inevitably fail at some point. This is with a refined solid, frequent recomputes of the entire model, and seemingly valid shape according to "Check geometry". The order in which you select the edges for filleting seems to matter but I can't figure it out. I'm very curious how GlouGlou (above) did it!

I'm also attaching my file, perhaps someone can see whether there is anything wrong with it that I missed. To be clear it is the fillets inside the pockets that don't want to play along. There is no issue with the top outer edge.

Code: Select all

OS: Ubuntu 18.04.5 LTS (XFCE/xubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22474 (Git) AppImage
Build type: Release
Branch: master
Hash: a44f8ffd427fa9b23b1f00dbf62d66cd152cd774
Python version: 3.8.5
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.4.0
Locale: Dutch/Netherlands (nl_NL)

[chrisb]

There was a challenge concerning this model in the german forum. If you cannot find it, I could give it a try.

[foosel]

Happy to report that the Access Violation no longer reproduces under

Code: Select all

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22474 (Git)
Build type: Release
Branch: master
Hash: a44f8ffd427fa9b23b1f00dbf62d66cd152cd774
Python version: 3.8.5
Qt version: 5.12.6
Coin version: 4.0.0
OCC version: 7.4.0
Locale: German/Germany (de_DE)

and also not under in a Linux VM with

Code: Select all

OS: Ubuntu 20.04.1 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22474 (Git) AppImage
Build type: Release
Branch: master
Hash: a44f8ffd427fa9b23b1f00dbf62d66cd152cd774
Python version: 3.8.5
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

Awesome!

Fillet obviously still fails, which is fine, my geometry needs some work. As long as the app stays usable such mistakes aren't as frustrating to learn from

We have a real open source and 3D-printing celebrity here! Thank you, foosel, for creating OctoPrint. I use it regularly.

Hi, glad to hear it's helping you

There was a challenge concerning this model in the german forum. If you cannot find it, I could give it a try.

Will try to dig it up, thank you!

[farahats9]

I have the same problem with fillets, I am new to FC (former solidworks and F360 user). The problem is that fillet bugs cannot be reproduced, sometimes the fillet works and sometimes it doesn't. Maybe it is something to do with the order I select edges ? any tips or workaround to make fillets work better?

I was testing the Model-Mania 2018 when the issue occurred. The program spams the message:

Code: Select all

Unhandled Base::Exception caught in GUIApplication::notify.
The error message is: Access violation

until it crashes.

My about info:

Code: Select all

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22411 (Git)
Build type: Release
Branch: master
Hash: d4519d5aec15bc08f029da5ed15410a494b57b2c
Python version: 3.8.5
Qt version: 5.12.6
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

[chrisb]

This object doesn't look too critical in terms of filleting. If fillets fail, retry with a very small radius, such as 0.01 and increase it until it fails. Look at the state just before: Are there any edges converging? Fillets cannot consume more then the adjacent faces and they often fail if vertices are involved, where more than 3 edges meet. Another cause of failure are very small or near to but not quite tangent edges.

For further detailed help you should give us more information:
- Upload the file
- tell us in detail where you failed to fillet with which parameters

[foosel]

My about info:

Code: Select all

OS: Windows 10 (10.0)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.22411 (Git)
Build type: Release
Branch: master
Hash: d4519d5aec15bc08f029da5ed15410a494b57b2c
Python version: 3.8.5
Qt version: 5.12.6
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

Try updating to 0.19.22474. It didn't fix my fillet troubles, but I no longer get the endless stream of Access Violation errors and non functional UI I did with 0.19.22411