5.1 volumetric fog not being affected by sky light or emissive materials and turning black

Hello, I recently updated my project from unreal 5.1 preview 2 to 5.1. When I opened my scene it looked completely different because the volumetric fog seems to completely ignore the sky light and emissive materials. All volumetric fog lit by indirect lighting is black and does not look nice. Previously (in 5.0 and 5.1 previews) sky and emissives would affect in the volumetric fog. I also tried a brand new scene in 5.1 and the same thing is happening. Is there a setting to turn this feature back on?

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Hello, I won’t be able to help you for the moment, it’s just to tell you that you are not the only one in this case, the volumetric fog of my project undergoes the same thing with the version 5.1. While looking for help I realised that there are many of us in this case. If I manage to find a solution I will let you know.

Good to know that I’m not alone. My scene is a dynamic day night cycle and in some cases relies heavily on the indirect fog contribution. I hope there is a fix out there, but if there isn’t unreal should patch this in a future version of 5.1 as the quality difference is massive. Here is before 5.1 and after 5.1


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I also have problems with dark volumetric fog. I thought that the problems were caused by the transition to SM6, but in version 5.1 p2 there are no problems.
I’ve noticed that most of my problems in the 5.1 release are fully working in the preview version.
Perhaps it makes sense to use the preview version as a basis (this is strange)

It’s the same with SM5 as well. The issue definitely was introduced with 5.1 final

Any solution to this ? Looks like fog is not receiving sky or indirect light. This happens even in new project.

@Sphinchs good news
in preliminary 5.1.1 (github branch https://github.com/EpicGames/UnrealEngine/tree/5.1) the problem with volumetric fog is solved, in my case it became even better than on 5.0.3, fewer artifacts.
I suspect this commit has fixed the bug (https://github.com/EpicGames/UnrealEngine/commit/d8efbe29f23e870bf8f0c3b85d58b06bc99423a1)

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Great news! I suspect 5.1.1 should come out shortly

Do you know when 5.1.1 should come out?

@AIGamez
I don’t have that information

Any news on 5.1.1? why has this not been patched yet?

5.1.1 has a lot of performance problems with Lumin and VSM, splash RHIT and landscape that turns into a minecraft map…
I think the team should be given time after the holidays.
In any case, 5.1.0\1 is not suitable (for me) to use it in production.
\\\
You can follow the fixes on github.
Branch 5.1
https://github.com/EpicGames/UnrealEngine/commits/5.1
Main branch (for the experienced, builds from this branch may not run or break the project)
https://github.com/EpicGames/UnrealEngine/commits/ue5-main

Was this issue really fixed in the latest 5.1.1 patch? I still don’t get any light distribution in volumetric fog with skylight. Could anybody else confirm if this was fixed? :thinking:

It’s definitely fixed

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Hm, alright! Thanks for clarifying that to me! ^^

@Arkiras I am curious if you could show me your heighfog and skylight settings? Also did you use static or movable skylight with lumen? I am still not getting any light in the volumetric fog which is very weird with movable skylight (directional light is working normally).

@Arkiras I am curious if you could show me your heighfog and skylight settings? Also did you use static or movable skylight with lumen? I am still not getting any light in the volumetric fog which is very weird with movable skylight (directional light is working normally).

I found out what the issue is, it does seem that if you have made a scene with 5.1.0 and you open it with 5.1.1 (with migration) it breaks either the skylight or the volumetric fog in the new project and the fog gets black. If I make a new project with 5.1.1 the fog issue persist with movable skylight, but not with static mobility with baking the light. Before it was working with movable skylight too.

There is another issue, in the moment I try to migrate the old project (5.1.0) to the new empty project (5.1.1) it breaks the fog. I also tried to add new skylight or fog, nothing fixes that, even if I delete all the maps and create new map it doesn’t fix it. Which means that something gets broken between the versions in the migration. I also tried making a new map in the old project and migrate it just that (without any 3d models etc. from the original map) it does breaks the new project making the fog black.

This isn’t optimal because it means that I have to do everything again in a new project. So I don’t consider the issue fixed, but maybe partly fixed or a feature regression is introduced with the fix.

It’s a movable skylight with Lumen yes. The only options I changed in the skylight are visible in the screenshot, the fog I changed the density to 1 and enabled volumetric fog. That’s it.

I can’t reproduce this… It’s working for me.

@Arkiras Thanks for your time clarifying the setup, but I am still surprised that it works for you. The only way I have made it to work is to bake a static skylight.

I made a short video showing everything I am doing with a clean installed UE 5.1.1. Maybe I am missing something that is only UE5 related? Are you using the source UE5 build or the Epic Launcher one?

Is there anyone else that may have this issue? I would deeply appreciate a help narrowing down the issue. ^^

Ok, after a lot tinkering I found out that the issue comes from the Cinematic Scalability. When I changed to Epic the light showed in the fog.

I am not sure if that is intented or a bug though. Anyway, thanks for the help @Arkiras!

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