Related articles:
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 |