Controlled random primitive

The first thing I did in 1983 was to create a primitive space-filling signal that would give an impression of randomness. It needed to have variation that looked random, and yet it needed to be controllable, so it could be used to design various looks. I set about designing a primitive that would be "random" but with all its visual features roughly the same size (no high or low spatial frequencies).

I ended up developing a simple pseudo-random "noise" function that fills all of three dimensional space. A slice out of this stuff is pictured to the left. In order to make it controllable, the important thing is that all the apparently random variations be the same size and roughly isotropic. Ideally, you want to be able to do arbitrary translations and rotations without changing its appearance too much. You can find my original 1983 code for the first version here.

My goal was to be able to use this function in functional expressions to make natural looking textures. I gave it a range of -1 to +1 (like sine and cosine) so that is would have a dc component of zero. This would make it easy to use noise to perturb things, and just "fuzz out" to zero when scaled to be small.