Houdini 22.0 Nodes Copernicus nodes

Cellular Noise Copernicus node

Generates cellular noise.

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Since 22.0

This node uses Worley noise to generate cellular patterns with controlled spacing and beveling. Use the Cellular Noise 3D COP if you want the source location to be the pixels' world coordinates instead of its image coordinates.

For example, use this node to create patterns that resemble skin, leather, cobblestone, pebbles, or dried earth.

Parameters

Type Info

The type information for the resulting layer.

See Type info for more information.

Range

Amplitude

A factor controlling the noise’s strength or intensity. Higher values increase the contrast between pattern elements; lower values reduce it.

Shift

The amount to increase or decrease the layer’s pixel value. Higher values increase the pixel value and overall brightness. Lower values decrease the pixel value and overall brightness.

Pattern

Element Size

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

Element Scale

When you turn on the Per-Component Controls option, this parameter scales the element size per axis to create anisotropic noise.

Jitter

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. You can turn on the Per-Component Controls option to adjust this further using the Jitter Scale parameter.

Note

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

Jitter Scale

When you turn on Per-Component Controls option, this is the per-axis scaling of the jitter.

Lattice Type

The grid to define Worley noise on and determine the cell shape.

Grid

Define Worley noise on a rectangular grid to create square base shapes. This is the common option.

Hexagonal

Define Worley noise on a so-called simplicial grid to create hexagonal base shapes. For higher computational efficiency, simplicial grids are made of triangles or tetrahedrons instead of regular cubes or squares.

Metric

The metric for computing the distance to a point.

Euclidean

Use the length of the line segment between the two axial points to define their distance. 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 their distance. This can result in diamond shapes. See Taxicab geometry for more information.

Chebyshev

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

Smooth Edge

When Metric is set to Euclidean, you can control the roundness of the cells.

Offset

Shifts 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 covers the entire standard image space (“canonical image”). If you have a non-square image, the values should match the aspect ratio.

Note

If on, values for parameters like Element Size 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.

Shape

Mode

Determines whether the shape parameters work as absolute values in image Space, or as relative values in the 0 to 1 range.

Absolute

Shape the cells using absolute values in image space.

Relative

Shape the cells using normalized values that are 0 at the cell border and 1 at the cell center. When Jitter is applied, a value of 1 corresponds to the most elongated cell that is possible.

Gap

The amount of space between each cell. Higher values increase the spacing between cells, and the cells will shrink until they're not visible.

Bevel

The amount of bevel to add to the outer edges of each cell. Higher values taper the cells inwards to create a pointy top. Lower values decrease the slope to create a flat top with hard edges.

Tip

When Metric is set to Euclidean, you can use this parameter in combination with Smooth Edge to create pebble-like shapes.

Bevel Ramp

A ramp to adjust the shape of the bevel. The left side of the ramp corresponds to each cell’s border, and the right side corresponds to the inset length given by the Bevel parameter.

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.

Note

This parameter doesn’t impact the output when there’s only positive values.

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

Outputs

noise

The computed noise.

border

An SDF Mono layer containing the exact distance to the border

between the two closest points. Use this to create even width cell boundaries.

center

A UV layer containing the image coordinates of the closest grid point. This can be used by a UV Sample COP to create a mosaic effect.

id

An ID layer containing the hash of the closest grid point. Note this can be negative.

See also

Copernicus nodes