flickering on trim sheet

cturbo

I am experiencing an issue with a trim sheet that contains detail and serves as a texture map on a plane. I have noticed flickering when viewed from an angle, which I suspect is due to the lighting, as this problem did not occur previously. Could anyone provide guidance on how to resolve the flickering issue?

Muzzoid

Are these trim sheets or decals?

If they are decals you are dealing with z-fighting, which is where you have overlapping geo that the model is not sure which one to draw ontop of each other, hence flickering.

Eric Chadwick

No I think this is caused by mipping, not coplanar faces.

You can try adjusting texture filtering methods in your game engine.

cturbo

It's not z-fighting; it's just a plane with a trim texture applied. Eric, could you guide me on where to find the settings to change? I'm still getting the hang of Unreal and I'm a bit lost. I tried searching online, but I keep finding information from different menus. I also came across some discussions about NVIDIA graphics cards causing flickering in Unreal 5. I upgraded to version 572.16 less than a week ago, and I didn't experience flickering before, so that might be the issue. Additionally, I saw some mentions of moiré patterns. Some of the instructions I found seem quite complicated, and I'm not sure where to begin
https://dev.epicgames.com/documentation/en-us/unreal-engine/temporal-super-resolution-in-unreal-engine#tsrflickeringtemporalanalysis

cturbo

I also observed that the flickering occurs when I'm at a distance, but it doesn't happen when I'm up close. I did some research and found a post suggesting that I enable mip maps. I followed a tutorial that involved adjusting the mip map settings, which did help reduce the flickering, but the quality looked lower when viewed from afar. I noticed that in the filter settings you recommended, there's an option for bi-linear, tri-linear, and nearest. I tried all of them, but none seemed to make a difference. Is there another setting I need to adjust?

Eric Chadwick

Usually it helps to use powers-of-two dimensions for textures, and to enable mip-mapping.

cturbo

yes it is 2048 x 2048 texture, i tried mip mapping and it doesnt stop the flickering when i adjusted the LOD Bias on the textures??

Eric Chadwick

You could try making custom mips, this might help. Parallel lines (or nearly so) are traditionally very difficult in real-time rendering as they recede. 

KiraMeow

this could be related to a moire illusion cause of your mips

cturbo

how do i fix it if it is? It wasnt doing that before, it was only when i started adding lighting then i noticed or could it be upgrading the gfx card? I have a nvidia 3090 gfx card and upgraded the driver to 572.60

Someone also suggested  it could be mobile mutil view checked in project settings but it is already unchecked.

Eric Chadwick

By editing the MIP maps. Fade out the normal map very quickly in the lower mips, and the diffuse too, any parts with high contrast.
http://wiki.polycount.com/wiki/Mip_Mapping

cturbo

Hey Chadwick, thanks for sharing that, can you just tell me where i need to go to access these settings to make sure i am doing it correctly or a tutorial which gives me the following instruction?

Eric Chadwick

I searched Google for "edit mip mapping unreal video" to find this:
https://www.youtube.com/watch?v=0VAhyIGyHig

cturbo

Hey, thank you very much! I gave it a shot, and it worked, but the image looked a bit pixelated. I went to the project settings, then to engine, and finally to render and default settings. I started toggling some options and found that the temporal upsampling feature was enabled, which was causing the flashing issue. Now that I've turned it off, everything's good! Yay! I'm not sure what temporal upsampling actually does or if it should be kept on.

Eric Chadwick

Awesome!

Muzzoid

cturbo said:

Hey, thank you very much! I gave it a shot, and it worked, but the image looked a bit pixelated. I went to the project settings, then to engine, and finally to render and default settings. I started toggling some options and found that the temporal upsampling feature was enabled, which was causing the flashing issue. Now that I've turned it off, everything's good! Yay! I'm not sure what temporal upsampling actually does or if it should be kept on.

Glad you found the solution.

Temporal upsampling is a technique to upscale the game and make it look higher res, it was a technique that existed before the latest AI upsampling technology.

Personally i much prefer just clean simple rendering, without anything temporal if possible. So yeah just leave it off. If gamers want this stuff on at the end, that's their call.

cturbo

great thanks for letting me know what that is. Im so glad i didnt end up redoing my textures and then to find out its just a silly button causing the problem.

poopipe

Eric Chadwick said:

By editing the MIP maps. Fade out the normal map very quickly in the lower mips, and the diffuse too, any parts with high contrast.
http://wiki.polycount.com/wiki/Mip_Mapping

its probably worth pointing out that Unreal really doesn't want you to do any sort of custom mip editing outside of the editor - you can fool it into letting you load a dds with mips but it's dirty. 

the other thing that you need to be really careful about is that mip loading is viewport resolution dependent  - i.e. custom mips that work at 1080p stand a good chance of not working at 4k 

as a rule I'd strongly recommend people stick to changing settings in editor and adjusting mip bias in materials rather than doing anything hacky 

cturbo

its good to know this thanks poopipe - it looked awful on 4k monitor