Houdini 22.0 Nodes Copernicus nodes

HeightField Erode Copernicus node

Simulates hydraulic and thermal erosion at a specific scale to create more realistic terrain.

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Since 22.0

This node uses rainfall and weathering to simulate the removal and transport of material, at a scale specified by the Feature Size. Larger scaled erosion can reshape terrain into broader landforms. Smaller scaled erosion can carve finer details. You can chain numerous HeightField Erode nodes together to create erosion features at multiple scales. See Erosion for a more detailed guide on eroding terrains in Houdini.

Parameters

Simulate

Turns on simulation, so the node updates with the Playbar. When turned off, the node simulates a fixed number of erosion iterations.

Iterations

When Simulate is off, the number of erosion timesteps to simulate. This controls the duration of the erosion process.

Reset Simulation

When Simulate is on, clears the entire simulation cache. ⌃ Ctrl-click to also reset to the start frame.

Start Frame

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

Substeps

When Simulate is on, how many iterations of the simulation to run per frame. Higher values create stronger erosion effects, but also take longer to simulate.

Caching

Cache Simulation

Turns on caching of the simulation. If the simulation is uncached, it will always have to cook from the start frame on any new frame.

Cached Frames

How many frames behind the current frame to keep cached.

Checkpoint Rate

The rate at which the node continually caches a single frame.

For example, set this to 5 to cache frames 5, 10, 15, and such. This allows random-scrubbing to be faster as it only has to re-cook from the checkpoint frame.

Set to 0 to turn off checkpointing.

Erosion Model

Feature Size

The width of erosion features, in meters. Higher values will create wider channels, slopes, and deposits. Lower values will create sharper features. The smallest possible feature size is 3× the input terrain’s pixel size. Features will be clamped to this size.

Spread Iterations

How many iterations of material transport to simulate in each frame. The number of iterations, together with the Feature Size, control the distance that eroded material can be transported within a single frame.

Random Seed

The seed used to randomize the erosion process. With each new value, the distribution of erosion features changes.

Erodability

How prone the terrain is to hydro and thermal erosion. You can use the erodability input to vary the softness of the terrain.

Hydro

Flow Force

The force of hydro erosion. With 0 you turn off hydro erosion.

Bank Angle

Controls the angle of channel walls. Higher values will create steeper channels that appear to cut deeper into the terrain, creating a jagged appearance.

Rainfall Coverage

The amount of rainfall to simulate each frame as a proportion of the terrain’s surface. This controls the intensity of hydro erosion in each frame. You can use the rainfall input to vary the rainfall across the terrain.

Slope Influence

Controls how closely streams will follow the slope of the terrain. Higher values will result in winding channels. Lower values will result in straighter channels.

Erosion Rate

The rate at which a stream erodes and accumulates material from the terrain.

Deposition Rate

Controls how quickly sediment is deposited once the stream’s transport capacity is exceeded.

Removal Rate

The rate at which a stream’s accumulated sediment decays. Higher values will reduce the amount of deposited sediment, allowing hydro erosion to cut deeper into the terrain, creating a rocky appearance.

Evaporation Rate

The rate at which a stream’s sediment capacity decays. Lower values will create more prominent channels that persist across longer distances with a rocky appearance. Higher values will create smaller local depressions with a soil-like or sandy appearance.

Thermal

Weathering Force

The force of thermal erosion. With 0 you can turn off thermal erosion.

Cut Angle

The angle that thermal erosion will cut until. A lower angle will make the cuts flatter, and allow for more thermal erosion to take place.

Repose Angle

The angle at which the thermal erosion debris will remain in place without sliding.

Inputs

height

The height layer to erode.

debris

An optional debris layer to update with the simulation.

sediment

An optional sediment layer to update with the simulation.

flow

An optional flow layer to update with the simulation.

erodability

An optional mask to vary the softness of the terrain.

rainfall

An optional mask to vary the amount of rainfall.

Outputs

height

The eroded height layer.

debris

A Mono layer containing the amount of deposited debris from thermal erosion.

sediment

A Mono layer containing the amount of deposited sediment from hydro erosion.

flow

A UV layer containing the flow of eroded material from hydro erosion.

Copernicus nodes