Houdini 20.0 Shelf tools

Small Ocean shelf tool

Creates a small patch of ocean complete with a material and depth information.

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This tool is useful for creating an ocean like surface. However, it is not a simulation, it is a deformer that does not use DOPs at all. You can scrub through the timeline and watch the ocean evolve without any simulation. For a simulated ocean, use the Wave Tank tool on Particle Fluids shelf tab.

Using Small Ocean

In the Oceans shelf tab, click Small Ocean.

The tool will create and wire the Ocean Spectrum and Ocean Evaluate nodes necessary to control the shape and movement of the ocean. It will also create an Ocean Surface shader and attach it to the newly created ocean_surface object.

The animation is driven by the Time parameter on the Ocean Evaluate node. The default expression is $T (the current time). You can edit this expression to change the animation direction and speed (for example, $T * 2 to make the ocean move twice as fast).


Change your shading mode to Smooth Shaded Mode to get a better view of the deforming ocean surface.

The ocean_preview node is used to preview your ocean surface in the viewport. The ocean_render node is used by the Ocean Surface shader at render time.

The Ocean Spectrum node has all of the tools for changing the look of your ocean. For example, on the Wind tab, the Speed will affect the amplitude of the waves, the Directional Bias lets you create waves that move more or less in one direction, and the Chop which allows you to create the sharp peaks on the waves. The Wave Amplitude tab also has some very useful parameters, such as the Scale which controls the size of the waves.


  • For rendering, this tool creates a fetch node at the output level which is connected to the compositing network inside of the ocean_render node. If you would like to generate displacement maps at render-time, you can connect this node to the input of a Mantra node. If you use the Render button on this Mantra node, you will cause the Ocean Evaluate node to generate the texture maps required by the Ocean Surface shader for the specific frame you are viewing.


    It is important to remember to use the Reset Simulation button on the ocean_render node to make sure your ocean preview and ocean render nodes are synchronized.

  • This tool also adds a Karma Ocean LOP on stage level for rendering the ocean in Karma CPU.

  • To generate spectrum geometry, click the Save to Disk button on the save_spectra node in the ocean surface network.


    Spectrum geometry will have to be re-generated if you alter the wave parameters.

  • For motion-blur at render-time you can add a velocity attribute. Go the ocean_preview node’s Geometry tab, and turn on Point Velocity. The information is stored on the points of your input grid. If you feel that the motion-blur is not accurate enough, you can change the rows and columns on your grid to increase the number of points. Keep in mind that drastically increasing the point count on your grid could negatively affect the speed of your renders.

  • If it is important for your scene to have information below your ocean surface, you can still optimize your renders by adjusting the Volume Step Rate and Volume Shadow Step Rate settings on the Sampling tab of the Mantra node. Often the volumetric element of the ocean is used for a general sub-surface scattering and attenuation effect and does not necessarily need to be highly detailed.

  • If the space below your ocean surface is not important in your final image, you could disable refraction on the Ocean Surface shader and turn off visibility on the ocean_interior object. This will reduce the length of your render significantly.

  • Lowering the Frequency on Ocean Surface shader > Foam > Streaks subtab will create a more broken up effect of the foam.

Changing the look of your ocean

To...Do this

Set the height of the wave

Navigate to the Ocean Spectrum node and adjust the Wave Scale parameter on the Wave Amplitude tab.

This value is multiplied by the Speed parameter on the Wind tab.

Set the direction of the waves

Navigate to the Ocean Spectrum node and adjust the Directional Bias parameter on the Wind tab.

This controls how many frequencies are moving in the same direction as the wind. Increasing this value will cause more frequencies to travel in the same direction, which is useful for creating shoreline effects.

You can also try increasing the Directional Movement parameter. This will dampen the waves moving in the opposite direction of the wind, leaving only the ones moving in the same direction.

Control the height of the peak

Navigate to the Ocean Spectrum node and adjust the Chop parameter on the Wind tab.

Increasing this parameter creates sharp peaks on waves. However, if this value is too high waves, may invert on themselves.

Add more detail to your ocean

Increase the Resolution Exponent parameter on the Ocean Spectrum node.


The Resolution Exponent parameter will not only determine the quality of your ocean, but also the size of the texture maps that you will eventually write out.

Create a large ocean

Use the Large Ocean shelf tool.

See also

Shelf tools

Using the shelf

  • Customize the shelf

    How to change the look of the shelf, change and rearrange its contents, and create your own shelf tools.