Absorption rate for the medium (rate per distance traveled in the medium, given in m−1). Set for each color component/wavelength separately. Default is (0, 0, 0).

Scattering rate for the medium (rate per distance traveled in the medium, given in m−1). Set for each color component/wavelength separately. Default is (0, 0, 0).

Radiant emittance of light leaving the surface.

Anisotropy factor, controlling the scattering direction between -1.0 and 1.0. Negative values give backwards scattering, positive values give forward scattering, and a value of 0.0 (the default) gives uniform scattering. Note that values smaller than -0.8 and greater than 0.8 tend to produce fireflies.

Scattering direction lets you control the look of volumes. Forward scattering, for example, is typically used for white clouds and smoke. Backward scattering is normally seen with solid materials like marble.

Performs a linear blend between the two anisotropy factors and allows for more complex effects such as rim-lighting on clouds.

Enables a secondary phase function, which is blended linearly with the primary anisotropy. This allows the phase function to include both forward (positive values) and backwards (negative values) scattering. This can improve volume rendering where you can fill the volume with backwards scattering, while maintaining the silver lining on the edges with forward scattering.

When the number of volumetric ray bounces reached the Modifier Start Level, the extinction coefficient is scaled by the power of this value. A value of 0 has no effect, while a value less then 1.0 exponentially reduces the extinction coefficient. As a result you’ll see brighter shadow regions, because the rays are less attenuated and exit the medium sooner with a fewer number of ray bounces. This effect helps to reduce rendering time for volumes that otherwise need many more ray bounces. To render a volume with multiple volumetric ray bounces, increase the Volume Limit on the Karma Render Settings LOP.

A constant multiplier for the albedo that is used in phase function. This helps to increase the direct lighting contribution. Values above 1.0 might appear softer and more translucent. To render a volume with multiple volumetric ray bounces increase the Volume Limit on Karma Render Settings .

When the number of volumetric ray bounces reaches the adjusted value, the Extinction Modifier and Contribution Modifer multiplier take effect. To render a volume with multiple volumetric ray bounces, increase the Volume Limit on the Karma Render Settings LOP.

volumeshader