Environment Fog

Enabled – Enables or disables the Environment Fog.

Fog 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.

Fog Color Multiplier –

Emission Color – Controls the fog emission (self-illumination). You can use this parameter to substitute the ambient illumination inside the fog, instead of using GI.

Emission Multiplier –  Multiplies the Emission parameter.

Fog Distance – Controls the fog density. Larger values make the fog more transparent, while smaller values make it denser. 

Fog Density – A multiplier for the Fog distance parameter that allows a texture to be used for the density of the fog.

Opacity Mode –

Fog Transparency –

Subdivs –

Use Height – Enable to specify height for the fog.

Height – If the fog is not contained within a volume, it is assumed to start from a certain Y-level height and continue downward indefinitely. This parameter determines the starting point along the Y-axis. Note the units are centimetres.

Solid Mode –

Solid Threshold –

Jitter –

Shadow Opacity –

Scale –

Deep Output –

IOR – Index of Refraction for the volume, which describes the way light bends when crossing the material surface. A value of 1.0 means the light does not change direction.

Fade out Mode – Allows you to choose between two different modes of fade out: Multiply by density or Add density to fallout.

Fade out Radius – Allows you to set a radius for the fade out of the fog.

Per Object Fade out Radius – When enabled, the fade out effect is applied to each fog volume independently..

Scatter GI – When enabled, the fog also scatters global illumination. Note that this can be quite slow. In many cases, global illumination within the fog can be substituted with a simple emission term. When this option is enabled, the currently selected global illumination algorithm in the V-Ray settings are used to accelerate GI inside the volume (e.g. the light cache or brute-force). 

Scatter Bounces –  When Scatter GI is enabled, this controls the number of GI bounces that are calculated inside the fog.

This sampler is used when any of the fog properties (color, density or emission) is mapped with a 3d texture. The sampler steps through the volume, evaluating volumetric textures and lighting, until it leaves the volume (if the fog is contained within a volume), or until the accumulated volume transparency falls below a certain cut-off threshold, or until a specified number of maximum steps is reached.

Simplify Texture for GI –

Step Size – Determines the size of one step through the volume. Smaller steps produce more accurate results but are slower to render. In general, dense volumes require smaller step sizes than more transparent volumes. In practice, step sizes that are two to three times smaller than the Fog distance parameter work well.

Max Steps – Specifies the maximum number of steps through the volume.

Texture Samples – Determines the number of texture samples for each step through the volume. This samples textures more accurately than the volumetric lighting. It is useful in cases where the textures vary much faster than the lighting itself (e.g. for detailed fractal textures).

Cutoff Threshold – Controls when the raymarcher stops traversing the volume. If the accumulated volume transparency falls below this threshold, the volume is considered opaque and tracing is aborted. Higher values make the rendering faster but may introduce artifacts. This parameter is not available when the render engine is set to GPU.

Light Mode – Allows you to specify which lights are considered when rendering the environment fog. It is used when you have certain lights affecting just specific objects in the scene while another group of lights is affecting the environment fog. Note that V-Ray GPU does not support light modes yet.

No lights – The lights in the scene do not affect the environment fog.
Use per-gizmo lights – The lights attached to the environment fog set are ignored. Only the lights affecting the shape where the fog resides are used.
Override per-gizmo lights – Only the lights affecting the environment fog set are considered.
Intersect with per-gizmo lights –  Only lights that are affecting both the shape and the environment fog set are considered.
Add to per-gizmo lights – Both lights that are affecting the shape and the environment fog set are considered.

Lights – Creates a list of lights to be affected by the Light Mode.

Use Shade Instance –

Use Shade Data –

Affect Background – Enables or disables the tracing of background rays through the volumetric.

Affect Reflections –  Enables or disables the tracing of reflection rays through the volumetric.

Affect Refractions – Enables or disables the tracing of refraction rays through the volumetric.

Affect Shadows –  Enables or disables the tracing of shadow rays through the volumetric.

Affect GI – Enables or disables the tracing of GI rays through the volumetric.

Affect Camera – Enables or disables the tracing of Camera rays through the volumetric.