Houdini 22.0 Nodes Copernicus nodes

Ocean Spectrum Copernicus node

Generates layers containing information for simulating ocean waves.

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Since 22.0

This node generates a set of layers that timelessly represent the evolution of ocean waves, modeling the effect of constant wind and tidal pull. Outputs of this node can be plugged into the Ocean Evaluate COP to animate the ocean surface height.

This node is similar in functionality to the Ocean Spectrum SOP.

Note

The Ocean Spectrum COP’s result is not as sharp as the Ocean Spectrum SOP’s output.

Parameters

Ocean Size

The world space size of the generated ocean spectrum. Increasing this value will fit more wave peaks and crests into a single ocean tile, and the waves will appear to move slower through it. For proper visualization of the height field generated by Ocean Evaluate from this spectrum, it should be uniformly scaled (transformed) by this amount.

Depth

The depth of the ocean. The waves in deep oceans have a strong dispersion relationship, meaning the large, low-frequency waves move faster than the smaller waves. Decreasing this parameter reduces the amount of dispersion and causes more uniformity in wave speed.

Gravity

Acceleration due of gravity. Waves have a shorter wavelength and move faster under stronger gravity.

Seed

Seed for random generation of the spectrum. Changing the seed will modify the spectrum without affecting the wave dynamics.

Wind

Spectrum Type

The algorithm used to generate wave amplitudes given various parameters such as water depth, wind direction and speed.

Phillips

The classic spectrum that provides control over wind direction in a fully developed ocean. This spectrum type is also known as Tessendorf.

TMA

An enhanced spectrum that adds additional parameters for how long wind has acted upon the ocean and performs better at lower Depth settings. The implementation of the TMA (Texel-Marsen-Arsloe) spectrum is also known as Encino waves.

Wind Direction

Wind direction in degrees, with zero being along the local X axis. This parameter controls the overall directionality of the spectrum.

Wind Speed

The wind speed. Higher wind speeds create larger low-frequency waves and generally increase the dynamic range of the ocean spectrum.

Swell

Enhances the directionality of the waves in the TMA spectrum when set to values greater than zero. Negative values remove directionality and adds more waves in directions opposing the wind.

Fetch (km)

The distance in kilometers that the wind has been acting upon the ocean in the TMA spectrum, often thought of as the distance from shore.

Wind Direction Bias

The amount that the waves in the Phillips spectrum will align with the wind direction. As this parameter increases, waves that don’t align with the wind will be dampened.

Directional Movement

The amount that waves in the Phillips spectrum will move in the same direction as the wind. When this value is low, the ocean will contain waves that are aligned with the wind, but moving in the opposite direction from the wind. Increasing this value will dampen those waves, leaving only those moving in the same direction.

Amplitude

Distribution

The random distribution used to scale the wave amplitudes after the shaping parameters have been applied.

None

No random values are applied to the amplitudes. This setting is useful for post-multiplying the amplitude volume with custom values before they are evaluated with Ocean Evaluate.

Uniform

Use a uniform random distribution, which gives amplitude to many wave frequencies across the spectrum.

Gaussian

Use a Gaussian random distribution, which tends to be the best match to experimental models of ocean spectra.

Log Normal

Use a Log Normal distribution, which gives higher amplitudes to fewer wave frequencies.

Normalize

The ocean spectrum is shaped by reducing the amplitude of waves traveling in unwatned directions, which causes the overall height of the ocean to change as the waves are shaped. Normalizing maintains consistent wave heights as the various shaping parameters are modified. When this parameter is enabled, the only parameters that affect wave height are the Wind Speed, which affects dynamic range, and Scale, which affects overall amplitude gain.

Reference Wind

The reference wind used for normalizing the overall wave height. Should only be changed if the units of your scene are changing.

Min Wavelength

Dampen any waves with a smaller wavelength than this value, which can help with aliasing of very small waves at very high resolution.

Scale

A constant gain by which to scale all the wave amplitudes.

Time

Loop Period

Length of the looping animation in seconds when looping is enabled.

Inputs

size_ref

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

Outputs

amplitude

Layer containing amplitude of each wave. If you would like to further adjust the generated spectrum, this layer is the most useful one to make modifications to.

frequency

Layer containing frequency of each wave.

phase

Layer containing phase offset of each wave.

See also

Copernicus nodes