This atmospheric shader node simulates the effect of light scattering, which causes more distant objects to appear lower in contrast, especially in outdoor environments.
The Fog shader can be found under Arnold > Volume > Atmosphere in the Material Manager.
Once you have created the fog shader, drag it onto the Atmosphere attribute in the Environment section of the Arnold Renderer settings.
Fog shader has the following attributes:
The color of the fog. Unsaturated values work best.
Fog distance controls the fog density. Fog density is modeled with an exponential distribution. Smaller values make the fog appear less dense, while larger values make it appear more dense.
This value changes the rate of the exponential decay along the direction axis.
Determines the axis for the direction of fog.
Determines the starting point for the fog along the axis set by the direction.