Ridged multi

This generation module, heavily based on the Perlin generation module, generates ridged-multifractal noise.

Ridged-multifractal noise is generated a lot like the Perlin noise, except the output of each octave is modified by an absolute-value function. Modifying the octave values in this way produces ridge-like formations.

Compared to simple fractals, multifractals have different roughness in different places. To achieve this, RidgedMulti derives weight of a given frequency from values of lower-frequency samples. Also, an offset is added at each step, and a gain value is multiplied in, creating a sort of feedback loop. This ensures that rough areas tend to become rougher, and smooth areas to become smoother. The resulting function is really great for terrain generation, creating both smooth valleys and rough mountain ridges.

The ridged-multi noise module usually outputs values between -1 and 1.

Node inputs/outputs

The module’s constructor needs:

The output value is a Generation Module

Examples

Frequency evolution

Frequency = 1

Frequency = 5

Frequency = 10

Lacunarity evolution

Lacunarity = 0.5

Lacunarity = 2

Lacunarity = 5

Octave count evolution

Octave count = 2 

Octave count = 6

Octave count = 12

Spectral weights exponent evolution

Spectral weights exponent = 0.4

Spectral weights exponent = 1

Spectral weights exponent = 2

Offset evolution

Offset = 0.7

Offset = 1

Offset = 1.3

Gain evolution

Gain = 0.5

Gain = 1

Gain = 2