Houdini 20.0 Nodes VOP nodes

General Fresnel VOP node

Computes the Fresnel reflection/refraction contributions and vectors for objects with or without depth.

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Since 14.5

This encapsulates the functionality of both the Fresnel and Thin Film Fresnel VOPs.

The amount of reflected light is output through kr, and the amount of transmitted light is output through kt. The normalized reflection and transmission vectors are output through R and T.

The global variables N and I will be used if the surface normal and incident vector inputs are not connected. If connected, the N and I vectors must be normalized.


Fresnel Blending

When off, disabled any fresnel term computation. In that case, both kr and kt equal 1.0.

Thin Film

Simulates an object with a thickness of 0, where light that hits the material immediately refracts or reflects out. The transmission vector T will not deviate from the indicident ray I.

Fresnel Style

Physically Based

Perform the physically correct fresnel computation.

Use Connected 'fresnel'

Use the value of the fresnel input as kr and 1.0-fresnel as kt.

Inside IOR

The refractive index of the surface material.

Outside IOR

The refractive index of the material surrounding the surface, usually 1.0 for air.



The surface normal. When not connected, the global variable N is used.


The incident vector. When not connected, the global variable I is used.

See also

VOP nodes