Houdini 18.0 Nodes Dynamics nodes

Whitewater Object dynamics node

Creates a Whitewater Object that holds data for a whitewater simulation.

The Whitewater Object DOP creates a Whitewater Object inside the DOP simulation. It creates a new object and attaches the subdata required for the Whitewater Solver to operate.


Creation Frame Specifies Simulation Frame

Determines if the creation frame refers to global Houdini frames ($F) or to simulation specific frames ($SF). The latter is affected by the offset time and scale time at the DOP network level.

Creation Frame

The frame number on which the object will be created. The object is created only when the current frame number is equal to this parameter value. This means the DOP Network must evaluate a timestep at the specified frame, or the object will not be created.

For example, if this value is set to 3.5, the Timestep parameter of the DOP Network must be changed to 1/(2*$FPS) to ensure the DOP Network has a timestep at frame 3.5.

Number of Objects

Instead of making a single object, you can create a number of identical objects. You can set each object’s parameters individually by using the $OBJID expression.

Object Name

The name for the created object. This is the name that shows up in the details view and is used to reference this particular object externally.


While it is possible to have many objects with the same name, this complicates writing references, so it is recommended to use something like $OBJID in the name.

Solve On Creation Frame

For the newly created objects, this parameter controls whether or not the solver for that object should solve for the object on the timestep in which it was created.

Usually this parameter will be turned on if this node is creating objects in the middle of a simulation rather than creating objects for the initial state of the simulation.

Allow Caching

By preventing a large object from being cached, you can ensure there is enough room in the cache for the previous frames of its collision geometry.

This option should only be set when you are working with a very large sim. It is much better just to use a larger memory cache if possible.


Color Particles By Type

Color the particles by their classification in the Whitewater Solver. By default the particle colors are:

  • Green - Spray

  • White - Foam

  • Red - Bubbles

  • Yellow - Ballistic

The Surface and Velocity fields sourced from the input fluid simulation can be visualized in a number of ways. The help for the Scalar Field Visualization or Vector Field Visualization provides more details about how these work.

See also

Dynamics nodes