I think bullet points of your goals might make this clearer, but I’ll try to take a crack at it.
First off, what does ‘moody’ post-processing mean? What mood: fear, claustrophobia, wistfulness, surealness, etherealness,etc?
What does ‘maintaining night’ mean to you? Keeping a clear night sky without things getting hazy and light pollution-y?
Managing volumetric fog can be done with particles, but you can also make volumetric fog exclusion volumes that take on brush shapes, you’d need to consult documentation to know how though. It’s cheaper than a lot of niagara calls.
Fundumentally, there aren’t a lot of ways to just generally optimize volumetric fog because it relies on, well, volume data. You’re telling the game engine to perform a light-scattering simulation for the some length of the camera frustrum, which is pricy. You can, via console variables or scalability settings, tweak some of the behavior: you could make the voxels for the fog bigger, which makes it blockier but consume less memory. You could make the ray-marching cheaper, but that’ll create artifacts and jittering. It’s all about tradeoffs. You could tell the volumetric fog to end early and replace with a cheaper height fog simulation, which is less robust but way more performant.
There are so many different ways to tweak fog behavior: you could adjust the exponentialheightvolume’s height cutoffs to make the ground foggier than the sky, you could adjust the scattering and extinction of individual lights to make them feel ‘thicker’ or thinner, you could tweak the PPvolume’s settings too. Note: ray-traced shadows won’t work with volumetric fog, it’s kind of one or the other rn without hacks.
Are you going for anything like this?
