Hey there, I am using UE4.27.2 and have faced with such a problem. When I bake the lighting CPU lightmass it seems like light is splitting into separate rays reminding dispersion effect. I have only one directional light and skylight in my scene. I have tried to reinstal Engine client and test it in UE4.26, but result was the same. It is interesing that when I am using GPU lightmass everything is ok.
Not sure if this is the exact same effect but this tutorial talks about weird banding effects with baking. Might be helpful
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Thank you for this tutorial, but undortunatelly it didnt help. Ive tried to set the quality to production in the Bake button menu, but its only make the result a little bit crispier. Increasing indirect lighting quality and other World settings parameters didnt help.
Are you encompassing the room in a lightmass importance volume?
Have you tried going into world settings and turning off compress lightmaps? Maybe it’s a compression artifact?
I pumped up my lightmass settings and getting rather good results. Lumen turned off so it’s just lightmass.
Added importance volume too.
First off, make sure you’re building your lighting on production. Area lights won’t resolve well on lower quality bakes. If that fails you may have to raise your ray count.
When you have a light with a very large source radius it will require a lot of shadow rays to resolve. By default Lightmass uses 16 penumbra shadow rays on Production Quality for area lights, which is good enough for most realistic source sizes, but not for larger ones. For that you’ll have to bump the ray count up, sometimes by a very large amount.
You can increase the penumbra rays by editing the setting in the Lightmass ini file in your engine (or more ideally, project) directory. This will probably affect bake times and memory consumption during the bake, but I don’t know how big the impact will be.
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Ive turned off compress lightmaps and placed an importance volume into the scene, but still no result
Have you tried changing lightmass setting in the world settings?
Yeah, actually Ive played with the ìndirect lighting intnsity, num skylight bounces and indirect lighting boucesand static lighting level scale`as well. It gets nothing but the tiny improvements.
If the level is small then could you upload it for tests. I’ve got a 32 core cpu that can chew through lighting pretty fast dialing in parameters.
Wow, I’ve got only 16 cores. I send you a similar scene that I tested on the office computer with the same troubles. That’s what I get using CPU and GPU Lightmass.
I’ve turned to production quality and then increase the number of penumbra rays up to 256. It really improved the result and I am already satisfied but do you see these small bandings? Maybe its the way the Engine works cause I turned down the indirect lighting intensity to zero in PostProcessVolume to see the result just of the direct lighting. Maybe its supposed to blend these bandings with indirect lighting further?
And @3dRaven when You will check the scene, please sure that the ligth source angle up to 10-15, button Use Area Shadows for Stationary light is on and the type of Directional Light is set to Stationary. Thanks a lot!
Some banding is unavoidable, on surfaces with materials it will be unnoticeable. You can try disabling lightmap compression if you haven’t already, but it probably won’t help very much (and will be extremely expensive)
Thanks a lot for your answer.
- Added lightmass importance volume
- boosted the samples
- reduced the static light level (less is better)
- turned off compression
still getting banding. It seems the post process is making it seem a lot worse though
Found what is causing the banding. It’s because you are scaling the GI value. It seems Unreal probably clamps the value or reduces it’s bit depth in the process or it could just be a bug.
Boosted packed light and shadow map texture size, indirect light quality, volumetric lightmap detail.
Thank you very much, for resolving this problem, It really gave me more knowledge about how Unreal works.