Feature Preview: Advanced Perlin Noise

I remember back when WM 0.9 was released, about 4 or 5 years ago now. There was a greyed out menu option for “Advanced Perlin Noise”. Those who asked at the time were told that it was experimental, and that it might eventually show up.

Fast forward to now. The Beta testers for 2.0 know that there is an Advanced Perlin device, but it didn’t yet have a user interface and at least half the features were missing/disabled. I’ve spent a good chunk of the last few days getting it to where it needs to be, so I’ll say a little bit here about it, and what it offers.

The Advanced Perlin Noise device is the logical successor to the Basic Perlin device that’s been in WM since the beginning.
So what’s different? A short list:

• A wider variety of noise basis types. These define the character of the terrain, so more variety equals more effects that can be achieved.
• Built-in elevation and steepness controls. You can now position the resulting terrain at any elevation, and control the steepness of the results, without using a clamp or biasgain device hooked after the noise device.
• Guide-controlled Parameters. You can hook up an input guide map to most of the noise parameters, and vary them across the terrain. For example, you can control the persistence, causing some areas to be smoother or rougher as you want them. The Layout Generator works very well as a input here.
• Shape Guide. The AdvPerlin device can use an input map as the first few octaves of noise, seamlessly integrating it into the resulting terrain. This allows you to use the rough shape diagrams you’ve created in layout mode to drive the synthetic terrain process.
• Enhanced Multifractal support. Unlike the original basic perlin, you may now use a variety of multifractal algorithms to vary the terrain. Think of this as being like the difference between a “Ridged Multifractal” and “Ridged” style in the Basic Perlin device, except using any style you want (not just ridged), and with several adjustable styles and parameters.
• Customizable Noise Spectrum. This is a big one: It allows you to specify the basis to be used for each octave of the fractal. Thus your terrain can shift in character as it moves from large scale to small.

These features tend to work synergistically — the whole is more potent than the sum of its parts. For example, let’s take a look at the noise style “Stephen’s Experimental” from the Basic Perlin device. That style was a musgrave-type multifractal using a ridged first octave and billowy style for the remaining octaves. You can recreate this style in the Advanced Perlin just by adjusting the settings for the noise spectrum and multifractal settings. But that is just one single style example among countless other types of terrain that you could create!
Clearly, a large array of presets will be more important than ever before for the Advanced Perlin, to keep track of and share interesting/unique noise types.