Houdini 16.5 Nodes VOP nodes

Oren-Nayar VOP node

Generates a color using the Oren-Nayar diffuse lighting model calculation.

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This is a more sophisticated diffuse calculation than Lambert’s. It provides a roughness exponent to control the spread of the diffuse contribution. Typically its color is the main surface color of the material. This lighting model is often used for materials with no specular contribution, such as clay or chalk or matte paint.

Inputs

nN

The normal vector is used in the Oren-Nayar diffuse calculation.

nI

The incidence direction ray used in the Oren-Nayar diffuse calculation,

Kd

The diffuse intensity.

diff

The diffuse color. This color is most often the main surface color of the material.

rough

A floating point value used to control the size or spread of diffuse contribution.

facefwd

This toggle will change the normal to face forward towards the camera.

Outputs

color

The Oren-Nayar diffuse color contribution:

Kd * diff * diffuse(nN, -nI, rough)

illum

Just Oren-Nayar diffuse lighting without the multiplication by the diffuse intensity or the diffuse color.

bsdf

The PBR diffuse calculation.

See also

VOP nodes