Houdini 20.0 Nodes VOP nodes

Karma Volume VOP node

Karma XPU compatible node for building MaterialX volume shader

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Since 19.5

Overview

This node combines parameters of Mtlx Anisotropic Vdf and Mtlx Uniform Edf and outputs volumeshader. Karma XPU currently has no support for MaterialX’s PBR nodes, so this node can instead be used to construct a volume shader.

  • Compatible with MaterialX nodes.

Inputs

Absorption

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

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).

Anisotropy

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.

Secondary Anisotropy

Please see Anisotropy for a description.

Secondary Mix

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

Emission

Radiant emittance of light leaving the surface.

Outputs

out

volumeshader

See also

VOP nodes