Houdini 19.0 Nodes VOP nodes

Lens Distort VOP node

A VOP that generates the offsets required to distort a Karma lens shader.

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Since 19.0

Overview

This is a lens shader component that generates the curvature offsets used to distort the Physical Lens Core node.

Parameters

Curvature Type

A type of curvature to distort the lens with: “None”, “Quadratic”, “Cubic”, or “Texture Map”.

Curvature Map

When Curvature type is “Texture map”, this is a path to the texture map. Values in the texture image represent the unit “height” of the lens (distance from flat) at a given position across the face of the lens. Black represents -1.0 and white represents 1.0.

Lens Curvature

When Curvature type is not “None”, this is the amount of curvature to apply, from -1.0 to 1.0.

Inputs

x

y

aspect

Outputs

offset

An offset for the ray direction’s Z value. This can be used to manipulate the curvature of the lens as it changes the direction of the ray. A value of 1.0 results in the ray being shot horizontally from the camera, and a value of 0.0 results in no change. Negative values can be also be input and they will point rays closer to the center of the lens.

normal

The normal of the curvature, this is an optional input when using the Curvature Offset parameter. Some curvature distortions may have an easily calculated normal which can be used to better estimate chromatic aberration through the distorted lens.

NOTE: This is only used when refracting rays in chromatic aberration, it can be ignored if chromatic aberration is not in use.

See also

VOP nodes