Everytime I use any resolution other than 1920 by 1080 (the standardsetting) like 4k, 8k or 2560 by 1440, the lighting of my scene gets altered and appears very flat and dull.
This is the original lighting how it actually should look like in1920 by 1080:
It looks a bit like the lighting settings I have done via the sequencer get overwritten or ignored if I change the output resolution. Not sure if this is really the case or what else might be the problem and how to fix it.
It looks just like there are some shadows missing here and there.
I seem to remember cryengine would have similar issues with higher resolutions. The lighting and the feeling somehow would change. The glow or bloom radius would get smaller, probably the AO would change also and so on.
Is this behavior the same for an environment without foliage ? Like if for example the place would be populated with stones and boulders.
Interesting. Indeed, if I delete all Foliage in my scene, the issue does not seem to appear and the Lighting seems to stay the same no matter whether it is rendered in HD or in 4K. So it looks like it has something to do with Foliage. Still no idea what causes it though.
I looked a bit closer in the 4k Foliage pic, and it looks like all shadows are missing. It’s like the foliage are demanding and “overwhelm” the memory of your graphics card ? So the graphics card has no more memory for the shadows. I’m not sure if that’s the case, but it sounds plausible.
How much RAM do you have on your video card ?
Are you using Virtual Shadows Maps ?
I am using a 3090 with 24Gb of Ram. Could be, that the Ram is sufficient for displaying all the shadows in HD but gets an overflow at higher resolutions.
The same effect also happens if I render in HD but increase the Screen Percentage value. However I cannot say at which exact value the lighting changes, all I know is that I get a normal lighting with Screen Percentage up to 150 and have the known issues with the changed lighting at Screen Percentage of 200.
Also at regular renderings without using Screen percentage at resolutions of 2560 by 1440 the lighting also changes. So it is not limited to 4k renderings.
Under Project Settings the “Shadow Map Method” says “Virtual Shadow Maps”.
If I switch this to “Shadow Maps” I get exactly the changed and incorrect lighting also in the viewport of the engine which I get in my final rendering at higher resolutions.
It nearly looks like the engine is switching from Virtual Shadow Maps to Shadow Maps during the rendering process if the rendering is increased above a certain output resolution.
Would there be any option to “outsource” the requirement for the Vram if this is really the problem? I am trying to create a pre-rendered offline rendering for doing a short cinematic. I do not want to create a realtime Game or so.
I hope it’s not the case, because I intend to use the exact same video card and I also wanna use tons of vegetation and also a very high resolution.
I thought you might have like 6 GB ram or something. I was under the impression that much ram would be enough and the virtual shadow maps has a clever solution for shadows, sort of like a mip maps for textures.
Speaking of which, are you using Virtual Textures ?
Or maybe there’s something wrong with the trees or vegetation used ?
EDIT: to recap, you should use virtual shadows, virtual textures, nanites everything, Lumen. With these and your card you should be able to render at least 4k.
I rendered with Virtual Texture Support disabled but enabled it after your recommendation in the project settings and rendered again but without any changes. 4k renders are still with the incorrect lighting.
The Shadow Map Method is on Virtual Shadow Maps, Nanite is enabled, Lumen is active.
All Foliage is purely Quixel Megascans either directly via Quixel Bridge or the Unreal Marketplace. As this is closely “Epic” and “Unreal” related, and Quixel is even an integral part of Unreal since Version 5 I think it should work properly with Unreal Engine?
Also I think if something is wrong, it must be wrong in all render resolutions. it should be unlikely it is working properly in HD but starts to to behave incorrectly starting from QHD upwards. But of course you never know when it comes to this type of stuff.
I’m not sure what else to say. Maybe someone else can chime in.
Is there a video RAM budget one can go over when rendering ? Can that “budget” be affected depending on the rendering resolution ?
I will do some tests, but I can’t right now, if I’ll find out something new, I’ll write here.
The problem seems to be solved!
The Attenuation Radius of one of my house lights was ridiculously high, basically including the whole scene and lighting the whole scene up, erasing any shadows in the trees.
However I still have no idea why this effect only kicked in in higher render resolutions but not during renderings in HD and why it seemed to only effect my foliage but not the rocks and cliffs.
Nevertheless, after scaling down my attenuation radius, everything seems to be rendering fine now also in 4k.
Thanks to everyone trying to help!
As far as I can see, looking at those two pics, HD and 4k, the shadows are missing from the rocks too, not just from foliage.
Can you make a test with an even higher resolution ? Like maybe 6k or even 8k. Only for a few frames. It’s possible your shadows will go missing again, the more you will increase the resolution. And again, if you will optimize your scene, like hiding all foliage, or parts of foliage, or making sure lights have proper radius, it’s possible your shadows will appear again even in a 6k or 8k res.
