Houdini 22.0 Nodes Copernicus nodes

Curl Noise 3D Copernicus node

Generates 3D curl noise.

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Since 22.0

This node generates a curl of 3D Perlin noise using a fractal approach. The output is a vector field stored as an RGB layer or Vector VDB. Unlike the Curl Noise COP, the source location is the pixel’s world coordinates instead of its image coordinates.

Use this node when you need a 3D divergence-free noise field, such as for a Distort or Flow Block Begin COP’s direction input.

Parameters

Signature

The layer type that the source accepts.

See Signatures for more information.

Range

Amplitude

The amount by which to multiply the noise, which the node applies before the Center adjustment.

For example, a value of 0.5 makes a pixel value of 0.5 become 0.25.

Note

Layers can store negative numbers and values above 1, so this may result in out-of-bounds values. You can use a Clamp COP to enforce the range afterwards.

Center

The center of the output noise range, which offsets the pixel values.

For example, a value of 0.5 makes a pixel value of 0.5 become 1.

Pattern

Element Size

The size (in world coordinates) of the basic element of the noise. You can turn on the Per-Component Controls button to adjust this further using the Element Scale parameter.

Element Scale

When the Per-Component Controls button is on, this is the per-axis scaling of the element size for anisotropic noise.

Offset

The amount to offset the entire noise function in world coordinates.

Fractal

Max Octaves

The number of times the noise is scaled and layered on top of itself.

Lacunarity

The amount to scale the noise for each iteration.

Roughness

The amount to scale the amplitude of each successive noise.

Octave Offset

The amount to offset the noise for each iteration.

Inputs

size_ref

A representative layer that determines the size of the output image and controls the metadata.

pos

An optional layer or VDB to use for the position of each pixel at which to evaluate the noise.

octaves

An optional octave amount that’s multiplied by the Max Octaves parameter.

roughness

An optional roughness amount that’s multiplied by the Roughness parameter.

Outputs

noise

The computed curl noise layer or VDB.

See also

Copernicus nodes