How to exclude room from the ExponentialHeightFog?
There are a few different ways to go about it, although it’s generally easier to add fog to a specific room than it is to remove it.
If the fogged area is relatively small, you could reduce the ExponentialHeightFog’s intensity to zero, but create a Volumetric Fog material, apply it to a mesh, and put that mesh wherever you’d like the fog. The ExponentialHeightFog actor needs to exist in the level to drive the fog, but it doesn’t have to apply fog globally.
Thanks for the answer.
Location - forest. There must be fog in the forest. But in a small house in the forest there should be no fog. The task is to subtract the small volume of the house from the large volume of fog.
Unless you’ve got the fog set very dense, it won’t be visible in the house, but would only show on distance shots, through the window.
You can also turn the fog off when you go in the house, something like this:
Thanks for the answer.
Of course, if the fog is not dense, then it is not visible in the room. But it affects lighting. Without fog, the room is lit more naturally. I’ll try to turn off the fog when the character enters the room. But then if you look out the window, the fog will not be visible.
Yeah, sorry, I don’t think you can cut a hole in it 
Thanks. I got it.
Seeing this in 2024, hope it helps. If you want to achieve an effect like in Subnautica for example, where you have no fog inside the base, but you can see the fog from a window, you should use scene capture components, and add them to the render target texture of the glass material. combined with a post process volume to turn the volumetric fog on and off when exiting and entering the building, this will give you the desired effect. I have not done it my self, but I can’t think of any other way to do it.
I wonder if the new LocalFogVolumes system could make a difference? It was designed to, in part, solve problems like this.