This page describes the V-Ray Scatter Fog feature.
Overview
The VRayScatterFog is a simple volumetric effect that traces light scattering inside a volume.
Image courtesy of Sung J. Bae
Parameters
Color – Defines the color of the fog when it is illuminated by light sources. You can also use a texture map to drive the fog color.
Color multiplier – A multiplier for the Color parameter.
Index of refraction – Index of refraction for the volume. If simulating a fog inside an enclosed volume light rays entering or leaving the volume are refracted based on this parameter.
Bias – This parameter allows to change the way the Color is applied. By adjusting it you can make thin parts of the volume to appear more transparent than normal, or less transparent than normal.
Thickness – This limits the rays that are traced within the volume. This is useful if you do not want or don't need to trace the whole volume.
Light multiplier – A multiplier for the scattered light.
Scatter coefficient – The amount of scattering inside the volume. A value of 0.0 means rays are scattered in all directions; a value of 1.0 means a ray cannot change its direction inside the volume.
Scatter direction – Controls the direction of scattering for a ray. A value of 0.0 means a ray can only go forward (inside the volume); 0.5 means that a ray has an equal chance of going forward or backward; 1.0 means a ray is scattered backward (towards the outside of the volume).
Scatter levels – Specifies the maximum number of scattering bounces.
Environment fog – When enabled the VRayScatterFog node is used for environment fog for the whole scene. This option should be disabled when the node is connected to a specific volume.