Bug Physics2D broken on iOS specifically

Hey,

We have recently updated our project from Unity 2021.1.28 to Unity 2022.2.20 and encountered a bug with physics2D. The physics on iOS behaves unexpectedly, in some cases objects with colliders and rigidbodies fall through other colliders and in other instances bouncing with weird impulses. This is specifically happening on iOS devices, the physics work fine in both editor and android. We have done some investigation and created a fresh project and been able to reproduce it again by building it for iOS. We simply have a square sprite with a rigidbody and boxcollider2d and a ground box with a collider. We have also noticed that when an object is pointed it behaves as expected. I have attached a video from an iOS device and the repro project. Has anyone else encountered this or have any suggestions on how to fix it?

Thanks!

Project:
https://drive.google.com/file/d/1yFuj1GK82-qOCLlRXS289S071Ld8Grf_/view
Video:
https://drive.google.com/file/d/1gIHuE2z6wcKs6XKSW6DLMtUyKxMLh0qG/view

 

I found the same exact problem happen only on ios device after I upgraded to the latest unity version, things are bouncing around randomly. someone suggested downgrading to 2021.3

 

Im now using packages in my project only available in 20222 so downgrading would break a lot of other stuff. Hoping someone from unity can respond to us.

 

Hi! Reported this a while back and finally got it confirmed in Feb. Unfortunately still no updates. Here it is on the issue tracker, so you can go and vote in hopes of a better visibility!

https://issuetracker.unity3d.com/is...es-gets-random-impulses-when-using-2d-physics

 

Hey @paljan, thanks! Cant believe this isnt a more common issue, no one must make 2d games for iOS.

 

First, sorry for kinda hijacking and mixing this up, as MelvMay seems to be responding to both of us now. I just wanted to add, that in the project we supplied to QA for the issue in the tracker that I was referring to, we are not using extrapolation, so it seems that is not the issue.

I can't understand how QA could have flagged it under 3D physics, but the back and forth we had was only due to services preventing the QA engineer from testing and verifying the project.

I'm just happy you've now recieved our report also and things are moving forward, as this is preventing us from releasing with newer version until the physics bug is fixed. It's still active in the 2022.3 LTS version.

@MelvMay Feel free to contact me with for example a direct message if you wish to discuss the already reported issue (UUM-27603) once you get it set up and tested!

 

Not sure if it's the same issue, but I'm also experiencing strange behaviour of 2D physics on iOS builds specifically. In my case, kinematic objects randomly start to move after collisions with certain objects (seemingly random) – which is not happening in the editor and in Mac builds. It happens in 2022.2.17 and looks the same after upgrading to 2022.3.0.

 

Hey, thanks for the reply.

I believe we did test a fresh project without the extrapolate option selected and still had issues. Il attach a video from our actual game where some of the assets just randomly start jumping around. I have just gone ahead and downgraded to 2021 again to get around it.

https://drive.google.com/file/d/16kxjieeT9_qkMRsNGUP-Ww7wiCQL62hM/view?usp=sharing

 

I was able to narrow it down, it's reported with a small repro as IN-43433. It happens when a capsule collides with a box using the flat part of the capsule. It also seems to have an impact what the value of velocity iterations is, if it's set to an odd value (e.g. 9 or 11 instead of 8), the kinematic object moves much faster after collisions. Anyway it shouldn't move at all, so it might be just a side effect of some other problem.

 

Yeah I just came from Unity 2021 and 2022.3.1f1 on iOS I have things bouncing everywhere in 2D after collision. The unity simulator works fine. Under 2021 it worked fine also. I can't go back to 2021 because I migrated and discovered my backup was not done first. So I hope this gets fixed.

 

Yep thats my exact problem. My bigger problem is I can't downgrade my app and never had a backup first. I know stupid right. So I hope it can be fixed moving forward.

 

WOW its still not working after installing 2022.3.2f1. This is starting to be areal problem.

 

Awesome , thanks mate. Legend

 

SNAP, sorry mate I thought the release came out with a possible fix in it, I got too excited when I saw it and never read what was in the release. I can't believe I dropped by and posted that and literally your post was there in less than a minute. Talk about timing. You sir are however a legend for locating and fixing the issue.

PS. Apologies , I know what its like when people are eager for solutions. I am a Senior Software Engineer as well. I get that all the time. I don't want to be that guy. Cheers

 

Thank you @MelvMay for solving this! Considering the report found it's way to you less than ten days ago, I'd say kudos to you and boo to the QA engineer tagging it wrong initially.

 

@MelvMay is there a difference between the backport from 2022.3.5f1 and the fix that will land in 2023?

 

Oh what a timing, Just started working on porting my android game into iOS... and this!

gameobject with 2d physics are falling through floor, flying all over. going crazy....

why... why...

 

Currently using 2023.1.1f1 ... will 2023.1.2f1 fix this issue? where is 1.3f1 I can't find it in hub q_q ....

 

+ It's fine on 2021.3.15f1 ... just Latest versions having issues i guess... sigh

 

@MelvMay

Thank you sunny klingon. I will wait <3 KAPLA!

oh and I noticed something while working on porting, Is it normal iOS version of game consuming much much more RAM compare to Android version?

 

Can you detail what was changed and what any possible side effects of those changes might be, so as to look for them. Building a physics heavy game.

and, thank you!

 

Thank you, very much, and well done. It often seems like I only use Unity because of your thoroughness with 2D physics, everything else about the engine feels (and is) far less reliable and often no fun at all.

 

Very seriously, this kind of diligence and rigour is a great relief to witness and rely upon. In a world increasingly casual about its ever more blatant disregard for thoroughness and its significance to that which can be built upon it, you are a diamond!

And I wish Unity would recognise this by focusing more specific endeavour around empowering the creation of highly performant and engaging/innovative games with 2D physics and its inherent advantages for parallax environments that embrace and enhance their play.

Particualry since "Play Mode" is the ultimate environment for rigging setting iterative experimentation for feel and responsiveness, configuration and relationships.

I get that 2D and 2.5D aren't glamorous, cutting edge, but Unity is so good at this, and so suited to it, thanks to your rigour with Box2D and extending and enhancing it, that it's a bit of a crying shame that there's not more provision and consideration going on around this category of Unity usage that celebrates and extends this capability to an extreme of its own.

 

And when that would be released ?

 

It's out, installing it now. Thanks.

 

I think maybe there is another problem now I can't get past my splash screen once deployed. I doubt that's physics related. My app loaded once and when I started game play that just hung as well. No code mods. I'll have to see what error is dumping on the screen when it does happen. It happens all the time but is intermittent. Sometimes just hangs on load. Anyone else having issues ?

This is 2023.1.3f1.

 

I need to use 2022.3.5

 

I mean, my project is 2022 stream. And the fix only come at 2022.3.5, so I can't check if it fixed as of now

 

I have restored a backup and gone back to 2022.3.4f1 and I am waiting until 2022.3.5 comes out. I am just continuing in UNITY environment and simulator for the moment. Hopefully it will deploy to iOS again as just running an app on iOS under 2023.1.3f1 was totally broken for me.

 

Any word on when 2022.3.5 will drop?