I have a scene in a game that is a dark environment and relies on the darkness in the distance to hide unloaded chunks from the player’s view. I love exponential height fog in the scene but I’ve found when the player walks into the fog from an overhead light it illuminates the darkness further down the map and lets the player see the edge of the currently rendered chunk. It looks like a ghosting effect as you walk into the fog and goes away a second after the player is stopped. As far as I’ve looked into there doesn’t seem to be any clear way to avoid this when there is a decent amount of fog coming from the light. Is there any way to disable something causing this?
Fog color is additive, which means it will illuminate anything behind it. What you could do is disable volumetric scattering on your lights where this is a problem, and fake the scattering effect with translucent cards/particles.
I would note however, this most likely won’t work with Lumen as Lumens screen traces have a similar problem.
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I hadn’t thought of this! This could work very well at distance but would break down a bit closer up. I’m coming to the conclusion that it is just a limitation of Lumen as of now, but I hope I’m wrong. Nonetheless thank you for the response and idea!
Hi, as i’m having similar issue. I’m using volumetric fog to get nice light shafts and a kind of atmospheric density but I don’t want players to be able to see what is in the darkness through the light shafts, for gameplay purpose.
It would be great if Epic could handle the issue and would give a parameter allowing to remove this unrealistic light/fog behavior.
Currently the only work around I found is to have real darkness in the dark areas. Meaning the geometries must be totally unlit. In this case you don’t see anything even through the lights scattering effects…
It’s doesn’t stop the unrealistic behavior that makes every other geometries, even when barely lit, to be clearer than it should be.
But well, it might help you to keep your unloaded chunks invisible to the player.
