Houdini 20.0 Nodes VOP nodes

Volume Model VOP node

A shading model for volume rendering.

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Since 14.5


This node manages the computation of opacity and lighting for volume shading of isotropic and Henyey-Greenstein reflection models. For a simple and easy volume shader, create a volume model VOP and promote the first density parameter to allow the geometry density attribute to contribute to shading.

For more information on building a material shader with VOPs, see creating materials.



Controls whether the density scale is specified as a single float or as a 3-component color.


Specifies the density. Normally this input should be bound to the density attribute by MMB clicking the input and selecting Promote Parameter.

Density Scale

Specifies a scale on the density value. While the density input is normally bound to geometry, this parameter can be promoted to modify the density used for shading.

Shadow Density Multiplier

Specifies a scale on the density value used for shadow rays. You can only decrease the density for shadows to allow more light to propagate through the volume than would happen physically.

Scattering Phase

Specifies the Henyey-Greenstein phase. A value of 0 results in isotropic scattering.

Smoke Intensity

A scale factor to control the overall reflectivity of the volume.

Smoke Color

The color of the light reflected from the smoke.

Emission Intensity

A scale factor to control the overall emission from the volume.

Emission Color

The color of emitted light.

See also

VOP nodes