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Overview

The Hydraulic Erosion filter provides highly adjustable simulated erosion. The filter simulates water raining on the terrain, moving downhill according to the normal of the terrain, eroding and depositing sediment along the way. In addition, it provides thermal erosion simulation, which describes the movement of sediment downslope due to the freezing/melting of water and the resulting movement of sediment into large piles at the end of slopes.


Parameters

  • Iterations
    The number of iterations the simulation will run for. A higher iteration count will result in a stronger effect.


  • Viscosity
    The viscosity with which the rain will run down the terrain.


  • Irregularity
    Adds a randomized strength to the erosion step to create a more organic result.


  • Evaporation
    The amount of water that is lost every iteration in each droplet.


  • Surface Erosion
    The strength of the erosion.


  • Angle Dependence
    Makes the erosion dependent on a higher slope. This protects flat areas in the terrain.


  • Level Erosion Multiplier
    Links the erosion strength to the level step.


  • Max Erosion Depth
    The maximum amount of erosion that can happen per pixel.


  • Rain Strength
    The amount of rain that is dropped at the start of the simulation.


  • Rain Probability
    Assigns a spawning probability to each raindrop that is compared to a randomized value.


  • Angle Offset
    Changes the angle of the starting velocity.


  • Sediment Loss
    Loses a constant amount of sediment in each step of the simulation.


  • Sediment Deposit
    Controls the amount of sediment added to the terrain each step.


  • Sediment Fill
    Controls the amount of sediment at the bottom of a slippage.


  • Wind Direction
    Allows you to set a wind direction, which will influence a particle's movement direction.


  • Wind Strength
    Controls how strongly droplets will be affected by the wind.


  • Wind Randomness
    Allows you to add a random rotation to the wind direction to be applied in each iteration.


  • Thermal Erosion -  Speed
    The speed at which the thermal erosion takes place.


  • Thermal Erosion - Threshold
    A threshold value below which erosion does not occur.


  • Thermal Erosion - Smoothness
    Controls the smoothness of the resulting erosion.


  • Thermal Erosion - Max Thermal Depth
    Limits the amount of thermal erosion that can happen on each pixel based on a thickness value.


  • Thermal Erosion - Thermal Deposit
    Controls the amount of sediment added back onto the terrain after the thermal erosion process.


  • Thermal Erosion - Thermal Add Sub
    Adjusts the balance between adding and removing sediment from the terrain. Leave it at .5 to have a consistent amount of material in the scene.


  • Thermal Erosion - Thermal Type
    Switches between two different computation modes.


Results

base erosion
using thermal erosion and wind to create dunes