--- title: "aaOceanPrmanShader" canonical: "https://rmanwiki-26.pixar.com/space/REN26/19661569/aaOceanPrmanShader" format: markdown --- ![image](media://0ee5c55f-3a4b-46cf-be1c-ab20b6be050b) > Macro (toc) A Tessendorf Ocean generator. Code contributed by Amaan Akram ([www.amaanakram.com](http://www.amaanakram.com/)). This produces a bumped normal that can be fed into a displacement shader to create ocean-like waves. ### Input Parameters #### Resolution Specifies generated texture resolution. Valid settings are 3 through 7. Each value generates the following resolution: - A value of 3 generates a resolution of 128x128 - 4: 256x256 - 5: 512x512 - 6: 1024x1024 - 7: 2048x2048. #### Ocean Scale Size of the ocean patch in meters. Larger values "fit" a larger expanse of the ocean into the rendered geometry. #### Seed Seed for the random number generator. Different values produce different ocean patches. #### Current Time Current scene time in seconds. Use an expression to drive this parameter. #### Repeat Time Waves loop (repeat their shape) after the specified amount of time in seconds. #### Fade Fades (scales) the ocean vector displacement strength. #### Chop Amount The sharpness of the peaks of the waves is controlled by this parameter. Also affects foam values. #### Velocity Controls the size of the waves. Higher velocities make fewer, but bigger waves. Lower velocities make a calm ocean. #### Wave Speed Speed multiplier for waves. #### Cutoff Defines a smoothing factor for the overall ocean surface. Cuts off (removes) waves with wavelengths smaller than the specified value. #### Wave Height Height multiplier for waves. #### Wind Direction The direction the waves travel in. #### Damp Bias waves traveling in the direction of the wind. Value of 0 makes waves travel opposite to the wind direction. 1.0 makes the waves travel in the wind direction only. #### Wind Align Align waves perpendicular to the direction of the wind, as observed in shallow waters. #### Invert Foam Makes wave peaks appear white, instead of making wave troughs white. #### Gamma Gamma factor to apply to the eigenvalue output. #### Brightness Multiplier for the eigenvalues. #### Normalize Whether to normalize the eigenvalues. See *fMin* and *fMax*. #### fMin fMin and fMax are used to normalize the eigenvalues, which can go into negative and positive values. See render log for typical values on a frame. #### fMax fMin and fMax are used to normalize the eigenvalues, which can go into negative and positive values. See render log for typical values on a frame. #### Write File Writes out a full-float OpenEXR vector displacement map sequence in object space. #### Output Folder Path to the folder for output images. #### Postfix Provides any postfix to apply to the generated file to identify it uniquely. #### Current Frame Set an expression for the current frame for frame padded sequence names. #### Ocean Depth Slows down waves as depth decreases. #### Surface Tension Capillary waves that run on top of the ocean surface. For small-scale effects only. See the original [Tessendorf](http://jerrytessendorf.blogspot.com/2011/10/simulating-ocean-surface-jerry.html) paper for details. #### Invert T Inverts the t parameter for the manifold. #### Manifold Provides the domain over which to apply the displacement. Defaults to s,t. ### Output Parameters #### outputDisplacementRGB The bumped normal. #### outEigenvalueFloat The eigenvalues. ### Example Usage To quickly get a convincing-looking ocean render, we can use [PxrSurface](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661415) (using the Glass parameters) as the Bxdf. The only thing we want to tweak is the *Refractive Index* (eta), which we'll change to 1.33 to match the value of water. For the displacement, we can use the PxrDisplace shader. Connect aaOceanPrmanShader's *outputDisplacementRGB* output. Below is an example render with the default settings for aaOceanPrmanShader. The ocean is being lit by an environment light using the `Luxo-Jr_4000x2000.tex` texture that is included with RenderMan. ![image](media://5d3c0277-91dc-41a2-8a9f-43641822781d) *A calm ocean.* Depending on the size of the object, it may be necessary to increase the *Resolution* parameter. For the next render, because of the size of the plane, *Resolution* has been increased to 7. Also, *Chop Amount* is increased to 10.0. ![image](media://0ee5c55f-3a4b-46cf-be1c-ab20b6be050b) *Things are getting bumpy.* To add some simplistic white foam, we can add a diffuse layer to our ocean, by adding diffuse to our [PxrSurface](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661415). Create a [PxrLayerSurface](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661463) shader, and connect the *outputDisplacementRGB* output to the (diffuse) *Bump* parameter and set the (diffuse) *Color* to something closer to white. Make sure that the specular and clear coat lobes have been disabled. For the layer mask, we can use the *outEigenvalueFloat* output from the [aaOceanPrmanShader](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661569) pattern. It's necessary that the values fall into the 0-1 range. We can easily enforce that by using a [PxrRemap](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661685) node. Connect the PxrRemap to the layer mask parameter. Because PxrRemap only works with colors, we can use a [PxrToFloat3](https://renderman.atlassian.net/wiki/spaces/REN26/pages/19661715) to convert the *outEigenvalueFloat* to a triplet. Set the *Input Min* and *Input Max* to -5 and 5, respectively, on the PxrRemap node. Lastly, turn on *invertFoam* in the aaOceanPrmanShader node so that the white appears at the wave peaks. You should then get a render similar to the image below. ![image](media://8a052dd8-9701-4e2b-a074-dd352b6d2e92) *Not so calm anymore.*