Advanced Perlin Noise

Advanced Perlin Noise is a highly customizable fractal terrain generator based upon the basic fractal noise techniques pioneered by Ken Perlin.

Perlin Noise works by layering multiple sets of blobby-looking noise patterns together. These layers are called octaves. The multiple octaves are combined together in a variety of ways to create the final result. Advanced Perlin Noise gives you total control over the types of noise used in each layer, as well as how they are combined. This allows you to create some very unique terrain shapes. 

Device Parameters

Feature Size Controls the density of features of the terrain. 
Feature Size roughly corresponds to the distance between major peaks or valleys. Small values produce quickly changing terrain, suitable for hills or lumps, while middle values are ideal for mountains. Large values allow continents and other shapes that are created on a massive scale.
Style Change the type of fractal noise that is produced.
Basic: Classic Perlin Noise. The resulting terrain looks something like very rough, jagged mountain terrain.
Ridged: Ridged Perlin has a very different character. Sharp discontinuities are laced throughout the terrain at all scales; these can look like ridges and spines in the terrain.
Billowy: The inverse of Ridged Perlin, the Billowy style produces terrain that has a lumpy appearance with sharp depressed creases throughout.
Smooth Ridged: Smooth Ridged style is similar to the Ridged style but has a smooth top to the ridges instead of sharp ridges.
Smooth Billowy: Smooth Billowy has lumpy shapes that have smooth creases throughout.
Sharp Ridged: Sharp Ridged is like the Ridged style but has even steeper walls than the regular Ridged style.
Flat Middle: As the name implies, this style uses a shape that has a flattened middle area, providing a broad band of smooth terrain shapes with steep peaks and valleys.
Terraced: The terraced style has a sharp drop in the middle altitude region. When layered together, it etches these drops all across the terrain.
Stephen’s Choice 1: A multifractal variant created by Stephen Schmitt, author of World Machine. It has large-scale ridges much like the ridged variant, but at smaller scales it takes on much of the character of the billowy variant.
Octaves Controls the number of layers of noise that are used to create the fractal. The default setting, (automatic), determines the precise number of octaves necessary at the current detail level automatically. Low octave values can produce a very smooth and/or simple terrain, as well as being faster to compute.
Persistence Controls the degree to which the strength of each layer of noise is reduced as they are layered together. Low persistence values produce very smooth terrains, whereas increasing the persistence produces more detail (and spikiness). Unlike a low octaves value, all layers of noise are still calculated when using a low persistence, so that terrain features are smoothly introduced as the value is increased.
Elevation Center Adjust the typical middle height of the terrain. Changing this value will produce terrain that is predominantly at lower or higher elevations
Steepness Adjust the steepness of the grades in the terrain. Low values produce a flatter terrain; High values a steeper one.
Random Seed Changing the random seed will create new terrain that looks similar to the current one.
Guide Levels and Input The guide inputs allow you to guide the fractal combination process differently at different points in the terrain. To activate a guide, you must connect a device to the appropriate input.
Shapeguide lead-in level Allows you to set how many octaves of noise the shapeguide takes over. Higher values allow only smaller fractal variations through.
Distortion guide level Distortion can create some wild terrain effects, as the features are pulled and twisted like taffy. Higher values will produce more distortion.
Persistence guide level Allow the persistence to vary across the terrain. Higher values of the guide level will make the input values cause greater differences in the persistence.
Multiscale Fractal Parameters Multiscale Fractals are fractals that exhibit a different character at different scales. Often, this is based upon height, location, or other factors. These tend to produce more sophisticated or complicated terrains.
Activity Activity allows you to change how strongly the multiscale effect is applied.
Offset Offset determines at what elevation the fractal behavior begins to change its character. Since each variant uses the value here in a slightly different manner, the best guide to its use is experimentation.
Gain Another multifractal parameter, Gain typically controls the relative strength of the detailed versus smooth regions of the fractal. Low values are very smooth, while high values bring on the detailed nature more quickly.
Lead-in level The Lead-in level allows you to ensure that the first several octaves of noise are unaffected by the Multiscale behavior. This lets you ensure that the overall character of the land is not incredibly altered by the multiscale behavior.
Type There are several different multiscale combination methods; The best guide to them is experimentation, as often you will achieve unexpected results by changing them.
Signal Level: The multiscale character depends on the strength of the current octave of noise
Elevation: The multiscale character varies depending on the elevation of the current point
Bi-Signal Level: Multiscale activity kicks in at both extremes of the current octave of noise
Bi-Elevation: Multiscale activity kicks in at both extremes of elevation
Classical: A multiscale method similar to Signal Level, used in the previous version of World Machine
Customize Fractal Profile In a normal fractal noise type, each octave of noise uses the same basis function to define it. The Customize Fractal Profile option allows you to assign a custom type to each octave; this can allow you to produce some very unique terrain characteristics. Custom octaves are created from the lowest level (largest feature size) to highest (smallest).
+Octave Add a new custom octave of noise atop any existing ones.
-Octave Remove the topmost octave from the stack.
Clear all Remove all custom noise octaves
Edit Style Change the noise style for the selected octave
Edit Strength Change the strength of the selected octave level, from 0 to 200% of normal.

Updated on September 12, 2019

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