Houdini 16.5 Nodes VOP nodes

Normal Falloff VOP node

Generates a falloff value based on the relationship between the normal and incident vectors.

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This VOP uses the dot product of a surface normal and an incident vector to calculate the falloff value for curved surfaces. The return value will be one (1) where the normal and incident vector line up (parallel), and zero (0) where they are at right angles (perpendicular). This does not work on flat surfaces, since there is no variance in the relationship between the normal and incident vectors with flat surfaces. This VOP can be used to create glow effects, simply by multiplying it with a glow color and applying it to a sphere; or to soften edges by multiplying with the opacity. If inverted, it can be used to create an inexpensive Fresnel effect by multiplying it with the output color of an environment map;

Inputs

nN

The normal vector used in the calculation of the falloff.

nI

This is the incidence direction ray used in the calculation of the falloff.

exp

A floating point value used as the exponent in a power function

invert

This toggle will invert the result. This is useful for creating glows.

facefwd

This toggle will force the normal to face the camera.

Outputs

float

This is the amount of falloff.

See also

VOP nodes