Create Water

Automatically place rivers and lakes on the terrain.

Rivers begin when the contributing area uphill of a point surpasses a threshold value that you specify. The resulting stream flows according to hydraulic principles, seeking the most efficient route downhill and growing in size according to the drainage area served.

Lakes occur when the water flow reaches a depression and pools. The Create Water device will always create a lake if a depression exists. If you want to prevent lakes from forming, make sure you use the Flow Restructure device on your terrain prior to the Create Water device to remove any depressions.

How to Use

To use the Create Water device, add it into your world and then connect, at minimum, a heightfield into the primary input.

Minimum necessary devices to create water

When viewed in the 3D View, you’ll now see all components of the terrain:

Terrain with automatic river added


Make sure you’ve enabled “Scene Water” in order to view the water layer that you’ve just created!

Inputs

  • Primary Input – The terrain you want to create water upon
  • Water Input – If you have existing water data you want to preserve (such as from a River device), wire it into this input. This device will only create water until it reaches an existing water cell.
  • Precipitation Input – Provide a map of rainfall. This precipitation map controls how quickly rivers start and grow. Note that lakes will always be filled regardless of precipitation amount!

Parameters

  • Channel Head Area – Drainage area needed to initiate a channel, in square kilometers. This is further modified by your precipitation map if supplied
  • Channel Model – How complex a model of river flow to create:
    • None at all
    • Single pixel river paths
    • Varying width, depth, and speed based on water discharge
  • Minimum Water Depth – The minimum depth of carved channels and lakes. If you need rivers to be at least a certain size, this is a useful setting. It also can fix some issues with geometry z-fighting, etc.
  • Discharge Scalar – How quickly discharge should influence river size. Higher values will result in larger, deeper, and faster rivers.
  • Flow Speed – Adjust the flow speed of the resulting rivers.

Common Issues

Pocket Lakes

Typical input terrains will have many lakes at all scales.

Fix this by adding a “Flow Restructure” device directly in front of the Create water device.

Other Issues

  • Set a minimum water depth sufficient to create a proper channel for your rivers.

Limitations

This device may not work as intended when used in a tiled build.

Updated on April 10, 2019

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