I have a feeling this issue has more to do with me not understanding some basics of UE rather than this being a technical problem. But I can’t get exponential height fog to stop glowing by itself. No matter what color (completely black for example) i set on the fog actor it still emits a light color.
I do understand that a slightly glowing fog probably looks more realistic under normal circumstances. For example producing the look of bright morning mist. But I want to build a spooky dark night scene. Picture something like 1800s London.
I had a directional light in the scene with a very low intensity blue tint. It looks reasonably ok as a moon light so you can just barely make out the details in the scene. The exponential fog actor, however, lights up the scene like a strange glowing backdrop. It makes the scene look cartoonish even.
Not really knowing what I was doing I was guessing the fog somehow scattered the light from my directional light. I turned all and any scattering parameters down to zero but no difference. I even deleted the light source just to make sure it wasn’t scattered light that made the fog glow. But the fog keeps ”glowing” even with no light sources at all in the scene.
Is the exponential height fog always glowing by design or am I just doing something very wrong?
Not that I’m going for ultra realism, but dark fog colors just looks terrible. It looks more like black smoke, and that’s a pretty flattering description. Whatever color you pick is seemingly quite emissive. I think it’s a fair guess that exponential height fog was designed to be used in light scenes. Where the self glowing thingy most likely actually makes it look quite real.
I did experiment with a workaround though. I cranked up the lights in the scene to day light levels, but with a blue tint to it. I then added a post process volume to the entire scene and used a very low exposure setting for the camera instead. It looks much better with the fog. A lot. It actually solved another issue for me. Directional lights, in my case the moon, don’t respond very well to low intensity settings. There’s not much of a visible difference between, for example, 0.1 or 0.6 lux. There’s however a huge difference between 1.0 and 6.0 lux.
I’ve been struggling with fine tuning the light so the scene is barely visible. A spooky scene where you can’t tell what’s around the corners. The exposure setting in post process will let me fine tune the overall light (or dark, more so) very precisely. The fog’s self glow blends nicely into the scene’s now cranked up lighting. And then it’s all exposed down to night time in post process.
You do know you can just create your own post process volume material to power a post process fog right?
All explained here.https://youtube.com/watch?v=N4mkgbwLg7U
That said, the way you went about it makes sense too - just keep in mind that eye adaptation should be disabled, probably with the post process. You probably want to avoid the possibility of it being enabled by console or .ini files…