Houdini 16.5 Nodes VOP nodes

Pyro Color Model VOP node

Provides constant, artistic, and physically correct (blackbody) tint as well as color correction functions.

This node is designed to have most of its interface promoted up to the parent material. to promote the UI for this node, you must choose Promote Interface ▸ UI + Links + Inputs to trigger scripts on the node to promote and create parameters up on the parent node.

Parameters

Color model

Use point color (tint with Cd)

Multiply the color defined on this tab by the point colors from the geometry.

Color model

Constant

Shade with a constant color.

Ramp

Shade according to a color ramp.

Blackbody

Shade according to a blackbody radiation model.

Constant

Constant

The constant color to use.

Ramp

The ramp to use.

Blackbody

Temperature (K)

The temperature corresponding to an input value of 1. For example, if this parameter is 5000 (the default), then an input value of 1 means a temperature of 5000 degrees Kelvin.

Tone mapping

The blackbody algorithm’s output has a huge dynamic range.

Adaptation

Squashes or stretches the low end of the generated intensity, similar to exposing a photograph for shadows.

Burn

Manipulates the high end of the generated intensity.

Color correction

Color correct

When this checkbox is off, the node has no effect. This may be useful for debugging.

Gamut mapping

How to map "illegal" colors outside the color gamut.

None

No mapping. Don’t try to make the colors "legal", simply output the results of the correction functions.

Clamp

Clamp all values to 0-1. This will make all colors legal but throws away much of the information about the color (for example hue, saturation).

Absolute colorimetry

Moves the color to the nearest representable color in the color space.

Relative colorimetry

Like "Absolute colorimetry", but instead of moving the color to the nearest representable color (shortest distance), moves to the nearest color along the line from the current color to the white point.

The remaining parameters implement various standard color correction functions.

See also

VOP nodes