This tool creates a FLIP tank simulation of waves breaking on a beach or other shallow water terrain. This tool is similar to the Wave Tank, except it enables an option to ramp down ocean velocities in a certain direction across the length of the tank. Reducing the velocities allow the ocean waves to break naturally as the water get shallower. The FLIP Simulation uses a POP Advect By Volumes node to continuously add the ramped wave velocities to the simulation.
Similar to the Wave Tank, this tool creates a boundary layer of particles to suppress reflections at the edge of the tank, contribute ocean velocities back to the simulation, and maintain the water volume level to match the ocean. The boundary layer will by default be disabled along the maximum extent of the volume in the specified direction.
The Ocean Spectrum node allows you to shape the initial frame of your simulated ocean, and Ocean Source controls the outputs.
Tip
For more information, see the differences between ocean tank types help page.
Using Beach Tank
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Click the Beach Tank tool on the Oceans tab to create a tank.
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Select a polygonal object to be extruded and act as the main beach collision object. If you don’t choose an object, a default one will be created for you.
Changing the look of your ocean
To... | Do this |
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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.
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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.
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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.
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Add more detail to your ocean |
Increase the Resolution Exponent parameter on the Ocean Spectrum node. Note 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.
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Create a large ocean |
Use the Large Ocean shelf tool. |
Understanding the network of nodes
There are three important layers to focus on when creating your ocean. First create the ocean, next add whitewater, and finally add specularity for the whitewater.
Tip
Disable all whitewater nodes at the OBJ level while you work on your ocean, then disable the ocean nodes while you work on your whitewater.
The first set of nodes control the ocean itself.
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fluidtank_initial
controls the first frame of your simulation. This is where you can shape the initial frame of your tank with Ocean Spectrum and control the outputs with Ocean Source. This includes the size of your tank, the depth of the water etc. -
AutoDopNetwork
controls the simulation of your tank. This is where you will find the FLIP Tank and FLIP Solver. The FLIP simulation will contain SourceVolume DOPs to sink and source the boundary layer particles, and a POP Advect By Volumes POP to add ocean velocities to the simulation. -
fluidtank_fluid
is the result of #1 and #2 combined, and is where the results are rendered. After the simulation is done, this node collects the fluid particles, sets up a material, creates some nodes for surfacing to finish the effect. -
fluidtank_interior
is also used for rendering, and for creating the volumetric effect that one of the shaders applies to the interior of the fluid. It controls the volume beneath the surface, such as how cloudy or murky the water will appear.
The next set of nodes are to control the whitewater.
Note
To add whitewater to your simulation, use the Whitewater tool on the Oceans shelf.
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whitewater_source
is where the spray and foam is coming from. -
whitewater_sim
is where the whitewater simulated. This is where you can modify the animation. -
import_whitewater
is the result of #1 and #2 combined.
Note
Do not try to set up a whitewater simulation from scratch. Always use the tools. For more information about using whitewater, see the Whitewater help.
For more information see How to animate a wave tank with whitewater.
Tips for improving the look of your water
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The defaults for the tank will create a low res simulation, which makes it easy to animate. However, to create a nice looking render, you will need to change some of the defaults. For example, you will need to increase the number of particles in your scene. Decreasing the Particle Separation parameter to about
0.03
will create a simulation with approximately 30 million particles. -
Add an environment light to your scene. Water reflects and refracts a lot of the environment around it, so having an environment map in your scene will significantly improve the look.
Tip
In your Environment Map parameter, navigate to the
HFS/houdini/pic/
folder and choose the sky fileDOSCH_SKIESV2_${F2}SN_lowres.rat
.
See also |