Bug / Crash obi fluid unusable since 2021.2.17f1

[locque]

Thanks for your effort once again, I reported the bug and willl try to get some help on the unity forums.

I wonder why I keep having so many unreproducable issues with Obi. I tried importing most of my other assets in 2021.3, none of them cause this issue. It's only Obi, any idea what could be different about your asset that triggers this problem?

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Okay nevermind all that, I guess I wasn't thorough enough with my experiments or whatever triggers the bug is highly inconsistent.

I tried creating some more empty projects and importing Obi, and this time saying yes to converting the APIs prevented the issue. Not only that, but I can now actually use Burst for the first time since upgrading from 2019.4! All 2020 and 2021 versions prior to 2021.2.17f had the same index out of range problem, independent of whether or not I chose to upgrade the APIs.

Nevermind again, this only prevents the issue up until you enter play mode in a scene with obi components.

[josemendez]

Nevermind again, this only prevents the issue up until you enter play mode in a scene with obi components.

I was under the impression that this happened even in an empty scene? Are the +20000 SearchEnumerator calls only happening in Play mode?

Maybe this is a dumb thing for me to say, but if you're using Burst check that the Burst compiler is actually enabled and that the jobs debugger is disabled. Otherwise performance will be quite terrible, much worse than when using Oni.

[locque]

I was under the impression that this happened even in an empty scene? Are the +20000 SearchEnumerator calls only happening in Play mode?

It did happen in an empty scene. Up until now the search calls started happening immediately after importing Obi, without opening any scene. But now with the API upgrade during importing I managed to postpone that to launching play mode in a scene with Obi components. But once it happens it stays that way forever, even if you close and reopen the project.

Maybe this is a dumb thing for me to say, but if you're using Burst check that the Burst compiler is actually enabled and that the jobs debugger is disabled. Otherwise performance will be quite terrible, much worse than when using Oni.

Burst compilation is enabled, and safety checks are off. I'm not 100% sure about the debugger since that doesn't seem to exist in the dropdown menu anymore for 1.6.5. There only is something called Native Debug Mode Compilation, which is off.



I also tried removing it to see what would happen, and to my surprise nothing changed. I'm pretty sure I got errors in the console  when setting the obi solver to burst while burst was not installed in 2019.4, but there is nothing now and the solver works fine apart from the horrid performance caused by the search calls. Its not worse than outside of play mode though, so I'm pretty sure it has nothing to do with the solver.

[josemendez]

It did happen in an empty scene. Up until now the search calls started happening immediately after importing Obi, without opening any scene. But now with the API upgrade during importing I managed to postpone that to launching play mode in a scene with Obi components. But once it happens it stays that way forever, even if you close and reopen the project.
I also tried removing it to see what would happen, and to my surprise nothing changed. I'm pretty sure I got errors in the console  when setting the obi solver to burst while burst was not installed in 2019.4, but there is nothing now and the solver works fine apart from the horrid performance caused by the search calls. Its not worse than outside of play mode though, so I'm pretty sure it has nothing to do with the solver.

This is extremely strange. The pattern you describe could have something in common with how Burst compiles jobs: by default it uses async deferred compilation, so nothing is compiled until you run the code for the first time. Once it's compiled, it stays that way unless you modify the code. Seems like the sluggishness has something to do with Burst having compiled the code?

However this also happened with the Oni backend right? So even though the behavior pattern is consistent with how Burst works, I'm not sure if it's related at all.

I think only Unity can shed some light on this, at this point. I will post on the Unity forums to see if someone has come across a similar issue, but if possible please report this as a bug so that they can take a look at it.

[josemendez]

Here's the thread I've opened in Unity's forums:

https://forum.unity.com/threads/very-slu...t.1270382/

I'll let you know if I discover anything.

Edit: just found out that you have posted as well:
https://forum.unity.com/threads/2021-3-e...s.1270283/

[josemendez]

For anyone having the same issue and finding this post in the future, this was indeed a bug in Unity. See:
https://forum.unity.com/threads/2021-3-e...s.1270283/