Simulations¶

Nodes that run an algorithm as many times as the user sets.

Hydraulic Erosion¶

Simulates the effects of rain on terrain.

Processing time is not affected by the terrain's Density Level like other nodes. Mainly the Number of Droplets, and Max Droplet Lifetime increases/decreases speed of processing.

Seed¶

Randomize the location of all the rain drops. Is NOT stable/consistent.

Number of Droplets¶

Number of raindrops to simulate. Higher values increase processing time

Erosion Speed¶

Affects how much sediment to erode (remove) from terrain

Max Droplet Lifetime¶

The maximum amount of time (iterations) the droplet has to complete its travel throughout the terrain. Higher values allow for more droplets to complete their paths, though the default value typically is enough. Higher values increase processing time

Advanced¶

Inertia¶

The amount of inertia each drop starts with. Smaller values result in deeper grooves

Sediment Capacity Factor¶

Maximum amount of sediment each droplet can carry at a given time. Higher the faster the droplet is going. When capacity is met, droplet deposits sediment (adds a bit to the terrain)

Minimum Sediment Capacity¶

Amount of sediment the droplet will always carry

Deposit Speed¶

Affects how much sediment to deposit (add) to terrain

Evaporation Speed¶

Affects the lifetime of the droplet. Higher values reduce lifetime quicker

Gravity¶

Affects the speed of the water droplet.

Initial Water Volume¶

Initial size of each droplet

Initial Speed¶

Initial speed of each droplet

Example¶

Base Geometry	After Erosion

Understanding Erosion Settings¶

NBase Geometry before Erosion — Base Geometry before Erosion

Erosion Speed vs Number of Drops¶

Default Settings used unless otherwise stated

Default Setting	Value
Number of Drops	100,000
Erosion Speed	0.3
Max Lifetime	60
Inertia	0.5
Sediment Capacity Factor	4
Minimum Sediment Capacity	0.01
Deposit Speed	0.3
Evaporation Speed	0.01
Gravity	4
Initial Water Volume	1
Initial Speed	1

Number of Drops¶

Erosion Speed	1,000 Drops	10,000 Drops	100,000 Drops	1,000,000 Drops
0.01
0.05
0.1
0.3
0.5

Lifetime¶

10	30	60	200	1000

Inertia¶

0.0	0.15	0.3	0.5	0.75	0.99

Sediment Capacity Factor¶

0	2	4	6	8

Minimum Sediment Capacity¶

0	0.01	0.02	0.03	0.05	0.1

Deposit Speed¶

0	0.01	0.1	0.3	0.6	1

Evaporation Speed¶

0	0.01	0.1	0.2	0.5	1

Gravity¶

0	2	4	6	10	100

Initial Water Volume¶

0	0.5	1	1.5	2

Initial Speed¶

0	0.5	1	1.5	2

Placement of Math Nodes¶

Shrinking the height of your plane often makes eroded meshes look more realistic. Here are examples of the differences when you place your multiply node (or other shortening node) before and after the erosion node:

Multiply Before	Multiply After

Multiply Node before Erosion Node Layout	Multiply Node after Erosion Node Layout

Multiply Node before Erosion: angled	Multiply Node after Erosion: angled

Multiply Node before Erosion: top	Multiply Node after Erosion: top

Smooth¶

Average surrounding values for each Value once per Iteration

Iterations¶

The amount of times to go through and average the heights

Example¶

Base Geometry	Smoothed Edge: 200	Smoothed Grid: 200

High Pass Filter¶

Grabbing just the details. You then can add the result to other geometry to add details you wouldn’t normally have

Smooth 200	Smooth 20	Smooth 2

Thermal Erosion¶

Simulates erosion of ice-bearing permafrost by the thermal action of moving water. Basically, this node goes through the surrounding vertices of each vertex and moves sediment from the current vertex to the lowest vertex.

Thermal Erosion’s speed is dependent on the resolution of the plane and the number of iterations.

Iterations¶

Number of times to go through all vertices

Erode Amount¶

Amount to move from the current vertex to the lowest

Example¶

Base Geometry	Eroded Geometry

Understanding Erosion Settings¶

Iterations¶

10	50	100	500

Erode Amount¶

0.01	0.025	0.05	0.1	0.2