Houdini 21.0 Nodes Copernicus nodes

Grunge Aurora Copernicus node

Generates a pattern resembling an aurora display.

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Since 21.0

This node creates a pattern of leaking lines that resemble aurora streaks. The Aurora parameters control the amount, roughness, and weight of the horizontal lines that make up the pattern. For example, configure the pattern so the lines either fall like a wavy curtain shape or spiral.

Use this node as a building block for more intricate textures. For example, use this node to create light patterns in a night sky or water damaged walls.

Parameters

Range

Amplitude

The amount by which to multiply the pixel value (originally in the 0 to 1 range). The node applies this before the Center adjustment.

Values in the generated layer cover the range from C-A to C+A, where C is Center and A is Amplitude.

Note

Layers can store negative numbers and values above 1, so this may result in out-of-bounds values. Use Post Processing options to clamp the output.

Center

The center of the output pixel values, applied as an offset.

Values in the generated layer cover the range from C-A to C+A, where C is Center and A is Amplitude.

Note

Layers can store negative numbers and values above 1, so this may result in out-of-bounds values. Use Post Processing options to clamp the output.

Mask Contrast

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

Pattern

Element Size

The size (in image coordinates) of the basic element of the generated pattern. 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.

Offset

The amount to offset the entire pattern in image coordinates.

Tile Size

The size of a single tile of the pattern. The pattern 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.

Aurora

Distortion Strength

The amount of vertical distortion to apply to each pixel along the X-axis. Higher values vertically reshape the straight input lines into irregular contours.

Distortion Size

The roughness of the distortion for pixels along the X-axis. Higher values result in smoother, more coherent edges with less waves. Lower values result in rougher edges with more waves.

Streak Weight

The weight of samples along the trajectory, which are averaged as each pixel is distorted. This ramp acts as a multiplier on the pixel values when streaking, which affects the vertical profiles.

For example, moving Point 1 from its default left position (evaluating to 0) to the right increases the separation between the streaks. For more information about using ramps, see Ramp parameters.

Advanced

Maximum Steps

The maximum number of steps that are allowed when applying distortion. Increase this value if you notice stepping artifacts in the result.

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.

Outputs

grunge

The generated aurora pattern.

See also

Copernicus nodes