Hello,
I tried to migrate my project to 5.3 and somehow all of my materials are mixed up. When I change the scalability level, play the standalone game, play in viewport etc. It picks random materials from my project and assigns them to the meshes each time I do an action. Disabling nanite fixes the problem. Any ideas?
Hey there @VintsKlea! This definitely seems like a migration bug! Does it actually assign the material (you can check by looking into the details) or is it just rendering an incorrect material?
Non of the materials actually get set, when I check the static mesh in details it still has its own original material. It just seems to be a rendering bug. Funny thing is, whenever I go into any material and save it, it fixes the whole map, until I press play again.
I even tried to migrate again both ways - trough the editor, so it automatically makes a copy and just by duplicating the project in Windows Explorer. Tried to do it on the same disc and on another m.2 SSD I have in my PC. Same problem. I found an old post saying I should redo my UV’s. Tried to do it on one of the meshes and the problem is still there. New UV’s or not.
Interesting! Could you backup your project, then recompile the shaders? This could be some odd caching issue. It may take a while if you have lots of shaders.
After backing up use this command in the console:
recompileshaders all
Hello, thanks for the tip. I recompiled all the shaders, at first it froze my engine and I left it running for 2 hours. It pulled through and when I returned it looked promising, everything was normal, until I hit play and then it still randomized all the materials 
.
Any more ideas?
Hrm, starting to believe this might be an issue with the way nanite handles the materials after the migration, though I can’t replicate the same on my side (I’m migrating a 5.2 project with some 2k texture Megascans meshes in nanite).
Does this affect freshly imported meshes as well?
Hey,
Yes. I just imported 2 new meshes. I let the editor make new materials for them based from the materials from Blender. Same thing happens after enabling nanite. If nanite is off, they are totally fine and don’t mix materials.
That is odd! Let’s dig a bit.
May I know your specs? (more specifically OS/GPU)
I’d recommend resetting your GPU settings in their Nvidia control panel or Adrenalin.
Does changing your AA settings affect it?
Does this occur in builds?
My specs are:
i7 13700KF
64GB DDR5
MSI Gaming Trio 4070ti
Asus Prime z790-a wi-fi.
Windows 11 Pro version 22H2, OS Build - 22621.2134
I updated my BIOS last week, also updated my CPU drivers. Got new Nvidia driver yesterday.
I reset my settings in Nvidia control panel to default. Both, under “Manage 3D settings - Global settings” and for “Program settings” for Unreal.
Anti-Aliasing is set to TSR by default. I tried all the other options as well. This doesn’t seem to affect anything.
I just built the game a few minutes ago and it does occur in build made with 5.3.
The issue has been reported as a bug.
I have the exact same problem on 5.3. The only difference is that I did not migrate at all. This is a fresh project started on 5.3.
Do you know if there a tracking number for this? I’m also having this issue, this is a major issue that prevents us from going to 5.3.
I’ve confirmed that this happens in packaged build, across a large array of different clients running the game.
Video of issue in action. Updating the skylight re-randomizes the materials.
I don’t think there was a ticket created for this.
I don’t think there was a ticket created for this.
For me it seems to be skylight related, If I remove the skylight, re-open the level, the material issue goes away. Does the same thing happen to you in your example?
Wow, you are absolutely correct. I never tested this but that does fix the issue for me aswell. At the expense of having no skylight now tho.
Yeah, removing skylights for all our levels and redoing the lighting is not an option for us. But maybe that information could help Epic resolve this problem, if it was ever looked at.
@VintsKlea - It would probably be good to not mark this as resolved as it will likely get ignored.
FYI - @SupportiveEntity
Good call. I just gave up on this problem tbh. I thought I’d wait for 5.3.1 to come out and migrate again. Let’s see if SupportiveEntity has something to say on this.
Thanks for the information @Skowroshima and @VintsKlea! It looks like the error is logged and in the issue tracker but has been backlogged. It seems that setting the skylight to movable has been a workaround for some users but obviously incurs some performance problems so may not be ideal. I do recommend submitting supplementary information regarding the bug referencing the issue number UE-116954 so if it can help an engineer solve it when the time comes!
Thanks SupportiveEntity. If this is the same issue, it’s made way more prolific in 5.3. If having the light as movable was a fix in older versions, it’s not a fix now.
We have a shipped title built in 5.2 where this is not happening. This prevents us from upgrading to 5.3. As this the severity of this has drastically changed with 5.3, is there a way to reevaluate the status of it?