Houdini 22.0 Nodes Copernicus nodes

Curl Noise Copernicus node

Generates curl noise.

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Since 22.0

This node generates a curl of Perlin noise using a fractal approach. The output is a UV noise. Use the Curl Noise 3D COP if you want the source location to be the pixel’s world coordinates instead of its image coordinates.

Use this node as a direction input, such as for a Distort COP or Flow Block Begin COP.

Note

Without the fractal process, this node is mathematically equivalent to wiring a Perlin noise into the Slope Direction COP.

Parameters

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.

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 image 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 image coordinates.

Tile Size

The size of a single tile of noise. The noise periodically repeats in this size. The size is in image coordinates, so the default is for the entire default canonical image. If you have a non-square image, this should match the aspect ratio.

Note

If on, values for parameters like Element Size and Lacunarity are rounded or clamped to make them valid. This is because these types of parameters must meet certain conditions for the noise to be tileable.

3D Noise

3D Noise

Evaluates the noise in a 3D space. Use these parameters to control the third dimension, while the first two dimensions are the location in the image.

Animate

Implicitly adds time to the third coordinate.

Pulselength

The interval length (in seconds) of the noise’s pulse in the third dimension. Lower values increase the rate at which the noise changes, while higher values decrease this rate.

Timeoffset

The amount of time (in seconds) that’s added to the start frame.

Timescale

The amount of time (in seconds) by which to multiply the start frame. Higher values increase the rate at which the noise changes, while lower values decrease this rate.

Loop Length (sec)

The time (in seconds) at which to repeat the noise. This clamps other options to enforce periodic behavior. Turn this on to generate animations that seamlessly loop.

When off, the animation generally doesn’t repeat after any amount of time.

Fractal

Max Octaves

The amount of times to scale add together the noise.

Lacunarity

The amount to scale the noise for each iteration, which is rounded to an integer value for periodic noise.

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 UV layer with a value that’s used instead of the pixel’s image coordinates for the noise.

time

Each pixel uses this layer’s value for the time.

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.

See also

Copernicus nodes