Exponential Height Fog

The Exponential Height Fog actor is used to create fogging effects such as clouds, but with a density that is related to the height of the fog. It renders the fog such that its density grows exponentially based on the height and falloff parameters. It supports adjusting the fog inscatter color, density, start distance and other artistic parameters.

Also, Exponential Height Fog is used by Volumetric Fog.

Properties

Option	Description
Fog Density	Fog density factor.
Fog Height Falloff	The fog height density factor that controls how the density increases as height decreases. Smaller values produce a more visible transition layer.
Fog Inscattering Color	Fog color.
Fog Max Opacity	Maximum opacity of the fog.
Start Distance	Distance from the camera that the fog will start, in world units.
Fog Cutoff Distance	Scene elements past this distance will not have fog applied. Setting this value to 0 disables it.
Directional Inscattering
Light	Directional light actor used for Directional Inscattering.
Exponent	Controls the size of the directional inscattering cone used to approximate inscattering.
Start Distance	Controls the start distance from the viewer of the directional inscattering, which is used to approximate inscattering.
Color	Controls the color of the directional inscattering, which is used to approximate inscattering from a directional light.
Volumetric Fog
Enable	Whether to enable Volumetric fog. Graphics quality settings control the resolution of the fog simulation.
Scattering Distribution	Controls the scattering phase function - how much incoming light scatters in various directions.
Albedo	The height fog particle reflectiveness used by volumetric fog. Water particles in air have an albedo near white, while dust has a slightly darker value.
Emissive	Light emitted by height fog. This is a density value so more light is emitted the further you are looking through the fog.
Extinction Scale	Scales the height fog particle extinction amount used by volumetric fog. Values larger than 1 cause fog particles everywhere absorb more light.
Distance	Distance over which volumetric fog should be computed. Larger values extend the effect into the distance but expose under-sampling artifacts in details.