UE 5.5 Lumen volumetric fog brightens background

[Khadyko]

Hey! I run into an issue when volumetric intensity is increased on any light it’s “cone” brightens everything behind it. You can see that the corridor is completely dark, no light sources inside, but through the cone details in it becomes clearly visible. Makes it impossible to have full dark areas in the scene in cases you have it in the middle of the hallway for example as you can see on the 2nd image. Same setup works fine and as expected in 4.27 - similar to fog cards, no effect on background objects, just bright inside the cone.

Tried to check “Separate translucency” in project settings and various console commands with zero effect. Heard that this issue starts with UE5.3, but I haven’t yet tested it since I don’t have other versions installed currently.
Any ideas on how to fix this weird behavior?
Thanks in advance!

[Khadyko]

In case it will be useful to anyone. Seems like you can’t go with volumetric scattering intensity (VSI) on light sources higher then 1 now.

There are 2 most important params in fog - Density and Extinction Scale. Set both of them in the way that with VSI = 1 fog became super dense, much more then you need. That should be sort of overkill amount. Now you just go with lower VSI values, so you never go above 1. This way there is a minimal “brightening” effect when very close to 1 or not visible at all in a range 0-0,7.

For sure it’s not the best or suitable solutions for every case, especially exteriors (haven’t tested yet), but works