Height Fog
Fog that is denser near the ground
Also known as: Exponential Height Fog · Unreal fog · Atmospheric fog · Distance fog · Volumetric fog
Definition
Height fog is fog whose density falls off with height, so it is thickest near the ground and thins out above, as in a misty valley or at dawn. In Unreal Engine it is the Exponential Height Fog actor, with controls for density, height falloff, color, start distance and an optional volumetric fog that catches light and creates visible light shafts. Fog adds depth, hides distant pop-in and helps set a mood.
In production
Use fog for atmospheric perspective: distant objects fade toward the fog color, which makes scenes look larger and gives depth. Match the fog color to the sky and light, and keep the density low enough not to wash out materials. Volumetric fog costs more and needs lights that interact with it. In Unity, fog is set in the Lighting settings or in a Volume for HDRP.
Tools that use Height Fog
See also
Volumetric Lighting
Light scattered through a participating medium
Sky Atmosphere
Physically based sky and sunlight
Global Illumination
Light bouncing between surfaces
Tonemapping
HDR → display-range remapping
Depth Buffer
Per-pixel distance used to sort what is visible
Lumen
UE5 dynamic global illumination
Environment Scene Looks Flat
No sense of depth or scale