Houdini 22.0 Nodes Copernicus nodes

Ripple Block End Copernicus node

End of a Ripple simulation block

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Since 22.0

Note

Although the Ripple solver is in COPs, you need DOP level permissions to use it. This means that it is not available in Houdini Core, but only in Houdini FX, Houdini Apprentice, Houdini Indie, and Houdini Education.

The Ripple block simulates ripples propagating across an image layer.

Two parameters control how waves evolve over time:

This node defines the end of a Ripple simulation block and must be paired with a Ripple Block Begin COP.

Note

Compiled COP networks don’t support simulation.

Parameters

Time

Simulate

Turns on simulation so block outputs feed directly back into the inputs, which creates a feedback loop. This is useful for complex motion and simulations.

Reset Simulation

When Simulate is on, this clears the entire simulation cache.

Time Scale

When Simulate is on, this is the amount to scale the time inside the block. A value of 1 maintains the normal speed, a value greater than 1 speeds up the simulation, and a value less than 1 slows down the simulation.

Substeps

When simulation is on, each frame is divided into this number of substeps. Increasing the number of substeps improves simulation accuracy and can help maintain stability when high-speed ripples would otherwise cause instability.

Iterations

Amount of iterations to run in non-simulation mode.

Live Simulation

When Simulate is on, this turns on live simulation to provide an interactive, non-deterministic simulation mode. It simulates independent of the playbar and isn’t associated with any keyframes or caching.

This parameter (and its associated parameters) is intended as a sandbox mode where you don’t have to rely on the playbar.

Tip

Live Simulation doesn’t save the results like other simulation types in Houdini, so use a Stash COP to save results.

Toggle Live Simulation

When Live Simulation is on, this lets you pause and resume the live simulation.

Tip

You can also use the Live Simulation button to pause and resume live simulation. See Cooking controls for more information.

Live Tick

When Live Simulation is on, this is the current tick (frame) within the live simulation.

Caching

Caching of frames during Simulation mode.

Note

When Live Simulation is on, the Start Frame, Cached Frames, and Checkpoint Rate parameters no longer apply.

Caching

Turns on caching of frames.

Start Frame

When Simulate is on, this is the frame on the Houdini playbar where the simulation starts.

Cached Frames

When Simulate is on, this is how many frames behind the current frame to keep cached.

Checkpoint Rate

When Simulate is on, this is the rate at which the node continually caches a single frame.

For example, set this to 24 to cache frames 24, 48, 72, and such. This allows random-scrubbing to be faster as it only has to re-cook from the checkpoint frame.

Set to 0 to disable checkpointing.

Wave Parameters

Collision Threshold

When the collision input is used, this value sets the threshold at which the mask acts as a collider.

Wave Speed

Controls how fast the ripples travel from pixel to pixel. This is proportional to the change in image space when the buffer coordinate changes by one in either x or y.

Conservation

Controls how much wave velocity is kept over time. It directly affects how quickly the motion slows down.

A value of 1 means no velocity is lost. A value of 0.5 means half the velocity remains after one second. A value of 0 removes all motion immediately. Values outside the 01 range are not valid and will be clamped.

Spring

Controls the strength of the spring force that pulls pixels toward their rest value.

Wave motion is preserved by the wave speed, while the spring pulls values back toward the rest state. This can create additional ripples as the values settle.

Inputs

height

Wave height.

feedback

A cable of the current feedback data. This is fed back to the input. The structure of this cable must match the initial structure provided on the block begin.

collision

An optional Mono layer providing a mask of a collider.

Outputs

ripple

The output ripples.

feedback

A cable of the current feedback data.

See also

Copernicus nodes