Hi, Im trying to get some good dynamic lightning in my low poly UE5.3 project, but after month of desperate tweaking of all possible directional light, sky light and post process volume im actually losing it. Lightining on open space is looking good but if that shadow is inside other shadow its nearly pitch black.
I am using directional movable light, skylight, post process volume, Lumen ilumination, virtual shadow maps, nanite(not on landscape). Couldn’t it be the low poly graphics? Please help.
Hey there @AdamGaming_CZ! Welcome to the community! So shadow darkness depends on a number of factors, but usually what you’ll be adjusting for that is your skylight intensity scale this applies light evenly everywhere, which means you’ll probably lower the intensity of your other lights to compensate.
Shadows doesnt look that dark, thats great but scene looks very odd. I would like to keep the balance of realism and visibility idealy. I have tried to tweak directional light and skylight but shadows arent still so nice.
Issue is also that shadows arent rendering that far and with virtual maps i cant find the setting to fix it.
in the first post the directional light aka sun is rather dark. the color looks more like overcast. this will not add a lot of gi thru lumen. so the shadows remain dark. (also in a overcast scenario there wouldn’t be any hard shadows.)
for reference: i do semi stylized too for testing (cause that’s animation style). i use the same “hdri” even. i push 5-10 lux of sun and 1-3 lux of ambient, depending on the mood i want. that is at 0 aka neutral exposure ofc. you gotta take that into account when lighting. auto exposure f*cks up things.
but basicly you gotta get some sun energy in there to spread gi into dark areas. the ambient light can assist but is more or less a stylized approach at giving shadows a hue or some ambient color. not really good as a general lighting feature, cause if you use too much it drowns the scene.
yeh… give it some energy and hue and maybe it’ll warm up visually, a lit bit.
just some more… i dunno… inspiration?
a semi synthetic overcast with just ambient light. looks decent. hardly pushes gi tho. indirect doesn’t work on ambient light, for good reasons.
and overblown indirect on the sun light. you can get lumen to creep into well shadowed corners. there are limits ofc.
it’s all part of the art to make it look some sorta way. tweak things. 
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Did you ever happen to figure out this issue? I’m having the same problem when i dynamically change the post process volume during runtime and I’m starting to lose my mind trying to figure it out.
Sort of, i completly changed grass style, so it doesnt have shadow, but i tweaked settings somehow that it seems good to me.
Even though @glitchered suggested something about 10 lux light intesity i used this settings.
Also, using volumetric fog helped visual a lot.
Dynamic GI creates physically corrected ambient values in shadows. Relatively bright ground texture albedo is somewhere around 0.3, so after 2 bounces only 0.3x0.3 energy will reach shadows. And that’s assuming that those bounces don’t hit anything along the way. Basically your shadows will be pretty dark. And a single global exposure won’t be able to reconstruct a nice image out of it due to limited screen dynamic range. Same really as if you would take a photo without any processing:
To make it look better you can play a bit with local tone mapping. It’s much better at compressing large dynamic range into something what can be displayed on screen. It’s not perfect and there’s a limit how far you can push it before it starts creating halo artifacts, but it does really help here.
Further adjustments can be made by adding a tiny bit of skylight leaking to raise global ambient level and reduce the dynamic range, but not too much as it will flatten lighting.
You can check screenshots for both in our Fortnite postmortem blog post:
https://www.unrealengine.com/en-US/tech-blog/lumen-brings-real-time-global-illumination-to-fortnite-battle-royale-chapter-4
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It’s a common issue I hope devs report to Epic. The sky light at high intensities makes the images look washed out (like a cloudy day) and does not work as a good ambient light for sunny scenes. On the contrast, low intensities of sky light provide unrealistic dark shadows. The problem has to do with Lumen not producing enough indirect (or bounced light). The skylight also has an indirect intensity value that currently on UE 5.4 does not work and has no effect.
You may try to simulate bounced lighting manually by adding extra area and spot lights but it is not very time and resource efficient. A best use case for area/spot lights would be on the windows of interior scenes, because the Lumen’s sky light has a hard time shining enough light into interiors trough windows and doors without increasing its intensity to unrealistic levels. In other CGI software the solution to brighten shadows will be to increase bounced (indirect) lighting of the sky light. It would be cool to have a setting to make the sky light emit more light further into caves simulating more bounced lighting.
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