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Heightfield Erode

fields/heightfield-erode·v1.5.1

IN:1 OUT:1

SUMMARY

Heightfield Erode runs hydraulic and thermal erosion on the Height layer. Rain falls on the terrain, flows downhill, picks up material where the flow is fast and steep and drops it as sediment where it slows down, while slopes steeper than the Cut Angle weather into loose debris that slides until it rests at the Repose Angle.

Run a fixed number of Iterations per cook, or turn on Simulate to continue the erosion frame after frame with Reset and Freeze. Erodability and the falloff mark rock that does not erode, the Water, Sediment, Debris, Flow and Flow Direction layers can be written out for shading or scattering, and Visualize colors the terrain by elevation with the layers blended on top.

PARAMETERS

PAGEErode

Simulate	Simulate	Off erodes the input for Iterations steps every cook. On continues the erosion frame after frame, carrying water, sediment and debris over.
Reset Simulation	Reset	Restarts the simulation from the input height field.
Freeze	Freeze	Holds the current result: no more erosion steps until it is turned off.
Iterations	Iterations	The erosion steps run every cook (every frame when simulating; turning Simulate on sets it to 1). More steps carve deeper channels.
Erodability	Erodability	How easily the terrain erodes, both hydraulic and thermal. The falloff scales it per sample: 0 is rock that does not erode and gets no rain.
Random Seed	Seed	Numerical value that initializes the randomization. Used when Rainfall Coverage is below 1.
Drain at Edges	Drainedges	Lets water and sediment flow out over the edges of the height field instead of pooling there.
Do Falloff	Dofalloff	Weight the effect on each point by the Falloff Attribute. The falloff scales the Erodability and the rain, 0 is rock that does not erode.
Falloff Attribute	Falloffattr	The point attribute, 0 to 1, that weights the effect.
Invert Falloff	Invertfalloff	Uses one minus the falloff attribute.
Falloff Strength	Falloffstrength	Scales the effect of the falloff attribute.

PAGEHydro

Flow Force	Flowforce	The strength of the hydraulic erosion: how much sediment the flowing water can carry. 0 turns it off.
Rain Amount	Rain	The water added to a sample that gets rain, per step, in world units.
Rainfall Coverage	Rainfallcoverage	The part of the terrain that gets rain in each step, chosen at random. 1 rains everywhere.
Flow Rate	Flowrate	The part of the water level difference that flows to a lower neighbor per step. 0.25 is the stable maximum.
Slope Influence	Slopeinfluence	How closely the streams follow the slope of the terrain: higher values keep the water in the valleys, lower values let it spread over the water surface.
Sediment Capacity	Capacity	How much sediment fast water on a steep slope can carry. Higher values cut deeper.
Erosion Rate	Erosionrate	How quickly water under its capacity picks up material: loose debris first, then sediment, then bedrock.
Deposition Rate	Depositionrate	How quickly water over its capacity drops its sediment (into the Sediment layer).
Removal Rate	Removalrate	How quickly the carried sediment disappears instead of being deposited. Higher values leave fewer deposits and a rockier look.
Evaporation Rate	Evaporation	The part of the water that evaporates per step. Low values make lakes and long rivers.
Minimum Slope	Minslope	Keeps a little capacity on flat ground (as the sine of a slope), so flat water still carries sediment.
Max Erosion per Step	Maxerosion	The deepest cut and the highest deposit per step, in world units: prevents pits and spikes.

PAGEThermal

Weathering Force	Weathering	The strength of the thermal erosion: how fast slopes steeper than the Cut Angle crumble into debris. 0 turns it off.
Cut Angle	Cutangle	Slopes steeper than this angle (degrees) weather into loose debris.
Repose Angle	Reposeangle	The steepest angle (degrees) loose debris rests at: steeper debris slides down.
Bank Angle	Bankangle	The repose angle under water (degrees): the steepness of the river banks.

PAGELayers

Add Sediment to Height	Addsediment	Keeps the deposited sediment in the height. Off: the height is the terrain without the deposits.
Add Debris to Height	Adddebris	Keeps the loose debris of the thermal erosion in the height. Off: the height is the terrain without it.
Water Layer	Waterlayer	When set, writes the water depth (world units) into this layer.
Sediment Layer	Sedimentlayer	When set, writes the deposited sediment (world units) into this layer.
Debris Layer	Debrislayer	When set, writes the loose debris of the thermal erosion (world units) into this layer.
Flow Layer	Flowlayer	When set, writes the water discharge (the water running through each sample per step: the rivers) into this layer.
Flow Direction Layer	Flowdirlayer	When set, writes the direction of the water flow (a unit vector in world space) into this layer.

PAGEVisualize

Visualize	Visualize	Colors the height field (writes Color): the elevation through the Height Ramp, with every Layer below blended on top in its own color, in order.
[+]Height Ramp	Heightramp	The colors of the elevation, from the lowest to the highest point of the Elevation Range.
[+]Ramp Mode	Vismode	Clamped holds the end colors outside the range; Periodic repeats the Height Ramp (contour stripes).
Auto Elevation Range	Autorange	Follows the lowest and highest point of the height field every frame (measured on the GPU).
Elevation Minimum	Elevmin	The height shown with the first color of the Height Ramp.
Elevation Maximum	Elevmax	The height shown with the last color of the Height Ramp.
Layer	Vislayer	The number of layers blended in their own colors over the Height Ramp.
[+]Layer	Vislayer0layer	The layer shown in this color: Water, Sediment, Debris, Flow, Erodability, or Slope, the steepness of the ground in degrees where 90 is vertical.
[+]Color	Vislayer0color	The color blended in where the layer is high.
Opacity	Vislayer0opacity	How strongly the color covers what is below it where the layer reaches its Full Value.
Auto Range	Vislayer0auto	Takes the Full Value from the layer's highest value every frame.
Full Value	Vislayer0max	The layer value that shows the full color (with Auto Range off).
Threshold	Vislayer0start	The part of the Full Value where the color starts to fade in. Raise it to show only the strong parts of a layer, such as deep water or the main rivers.
[+]Layer	Vislayer1layer	The layer shown in this color: Water, Sediment, Debris, Flow, Erodability, or Slope, the steepness of the ground in degrees where 90 is vertical.
[+]Color	Vislayer1color	The color blended in where the layer is high.
Opacity	Vislayer1opacity	How strongly the color covers what is below it where the layer reaches its Full Value.
Auto Range	Vislayer1auto	Takes the Full Value from the layer's highest value every frame.
Full Value	Vislayer1max	The layer value that shows the full color (with Auto Range off).
Threshold	Vislayer1start	The part of the Full Value where the color starts to fade in. Raise it to show only the strong parts of a layer, such as deep water or the main rivers.
[+]Layer	Vislayer2layer	The layer shown in this color: Water, Sediment, Debris, Flow, Erodability, or Slope, the steepness of the ground in degrees where 90 is vertical.
[+]Color	Vislayer2color	The color blended in where the layer is high.
Opacity	Vislayer2opacity	How strongly the color covers what is below it where the layer reaches its Full Value.
Auto Range	Vislayer2auto	Takes the Full Value from the layer's highest value every frame.
Full Value	Vislayer2max	The layer value that shows the full color (with Auto Range off).
Threshold	Vislayer2start	The part of the Full Value where the color starts to fade in. Raise it to show only the strong parts of a layer, such as deep water or the main rivers.
[+]Layer	Vislayer3layer	The layer shown in this color: Water, Sediment, Debris, Flow, Erodability, or Slope, the steepness of the ground in degrees where 90 is vertical.
[+]Color	Vislayer3color	The color blended in where the layer is high.
Opacity	Vislayer3opacity	How strongly the color covers what is below it where the layer reaches its Full Value.
Auto Range	Vislayer3auto	Takes the Full Value from the layer's highest value every frame.
Full Value	Vislayer3max	The layer value that shows the full color (with Auto Range off).
Threshold	Vislayer3start	The part of the Full Value where the color starts to fade in. Raise it to show only the strong parts of a layer, such as deep water or the main rivers.
[+]Layer	Vislayer4layer	The layer shown in this color: Water, Sediment, Debris, Flow, Erodability, or Slope, the steepness of the ground in degrees where 90 is vertical.
[+]Color	Vislayer4color	The color blended in where the layer is high.
Opacity	Vislayer4opacity	How strongly the color covers what is below it where the layer reaches its Full Value.
Auto Range	Vislayer4auto	Takes the Full Value from the layer's highest value every frame.
Full Value	Vislayer4max	The layer value that shows the full color (with Auto Range off).
Threshold	Vislayer4start	The part of the Full Value where the color starts to fade in. Raise it to show only the strong parts of a layer, such as deep water or the main rivers.

PAGECommon

Bypass	Bypass	Pass through the first input to the output unchanged.
Free Extra GPU Memory	Freeextragpumem	Free memory that has accumulated when output memory has grown and shrunk.

INPUTS

Input 0 POP - Heightfield

OUTPUTS

Output 0 POP - Heightfield