Perlin noise is a mathematical function that generates smooth, continuous sequences of values, often used to create natural-looking randomness in computer graphics. In P5.js, the noise() function provides access to Perlin noise, producing values that change gradually as the input changes. This is very different from the random() function, which generates independent, unpredictable values every time it is called.

When you use random(), each number has no relationship to the previous one, which can result in jittery or chaotic motion. By contrast, noise() is ideal for animating objects in a way that feels organic and lifelike, since each new value is smoothly related to the last. This makes Perlin noise a powerful tool for simulating natural phenomena such as flowing water, drifting clouds, waving grass, or the gentle motion of creatures.

In generative art, you use Perlin noise to control movement, shapes, and patterns that should feel more like those found in nature. The result is artwork that appears less mechanical and more expressive, with subtle variations and fluid transitions that are pleasing to the eye.