Houdini 21.0 Nodes Copernicus nodes

Fractal Noise 3D Copernicus node

Generates fractal noise from 3D locations.

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This node generates a noise pattern using a fractal approach. The same underlying noise is sampled at increasing frequencies and mixed together. Unlike the Fractal Noise COP, the source location is the pixel’s world coordinates instead of its image coordinates.

For example, use this node to create cloudy, smoky, or TV static patterns.

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.

Noise Contrast

The amount of contrast to apply to the noise before the Amplitude and Center parameters. You can use this parameter to make the noise more extreme without exceeding the 0 to 1 range.

Pattern

Noise Type

The underlying noise function that’s iteratively sampled to generate the fractal noise.

Simplex

Create Perlin noise on a simplex grid.

Perlin

Create Perlin noise on a regular grid. This type of noise generates more natural results.

Worley Cellular F1

Create Worley noise using its primary distance value, which is the distance to the closest worley point. This generates a cell-like noise.

Worley Cellular F2-F1

Create Worley noise using the difference between its second closest and closest points. This generates a cell border-like noise.

White (Random)

Create white noise where each noise element is given a constant but random value.

Alligator

Create alligator noise to produce a bumpy output. This pattern resembles alligator skin.

Per Component

Computes a separate noise for each channel of the output. If off, the output is grayscale for mono and non-mono layers.

Metric

When Noise Type is Worley Cellular F1 or Worley Cellular F2-F1, this is how to define different metrics for computing the distance to a point.

Euclidean

Use the length of the line segment between the two axial points to define the distance between the two points. This can result in circular shapes. See Euclidean distance for more information.

Manhattan

Use the sum of the differences between the two axial points to define the distance between the two points. This can result in diamond shapes. See Taxicab geometry for more information.

Chebyshev

Use the maximum difference between the two axial points to define the distance between the two points. This can result in square shapes. See Chebyshev distance for more information.

Worley Jitter

When Noise Type is Worley Cellular F1 or Worley Cellular F2-F1, this is the amount of random noise to add to each point’s position on a grid. The random noise is added before the Worley noise measures the distance to the points.

Note

Values greater than 1 may produce artifacts because they jitter past the search radius.

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 anistropic noise.

Offset

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

Fractal

Max Octaves

The amount of times to scale add together the noise.

Lacunarity

The amount to scale the noise for each iteration.

Roughness

The amount to scale the amplitude of each successive noise.

Post Processing

Note

The node applies the post-processing operations in the order they're listed.

Fold

Sets the noise values to the absolute value. For example, a pixel value of -2 becomes 2.

Complement

Sets the pixel value x to 1 - x.

Note

This method works for values in the 0 to 1 range. For images outside of this range, using Complement results in negative or out of range values.

Bias

The amount to pull the medium grey values (around 0.5) towards zero (if Bias is less than 1) or one (if Bias is greater than 1). A bias value of 0.5 doesn’t affect the values.

Gain

The amount to pull the medium grey values (around 0.5) together, while values around 0 and 1 are pulled apart. A gain value of 0.5 doesn’t affect the noise values.

Gamma

The overall gamma of the generated noise. Values greater than 1 increase the range of values in originally bright areas, which darkens the noise. Values less than 1 stretch out the range of values for originally dark areas, which increases the overall brightness of the noise.

Contrast

The amount to expand or shrink the overall range of tonal values. Each noise value is pushed towards (if Contrast is less than 1) or away from (if Contrast is greater than 1) medium grey values (around 0.5).

Note

This is not the same as Noise Contrast, which appears in some noise nodes and applies contrast during the noise function.

Clamp Minimum

Clamps values below the specified threshold.

Clamp Maximum

Clamps values exceeding the specified threshold.

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 noise layer or VDB.

See also

Copernicus nodes