Maximilian Schönherr Offers an Overview for Working With 3 Random Number Functions in Maya, including Noise and Sphrand.
One of the most common reasons to work with an expression is to introduce a bit of randomness. In Maya, randomness works well for scattering, textures, animation and anywhere you need to break things up. Maya has a series of random number functions from which you can draw. They work well with position, motion, color or any other attribute, including those of particles. Maximilian Schönherr explains three different random number functions, working with Rand, Noise, and Sphrand.
In recent versions, Maya has added other methods to add randomness, including xGen and MASH. “Many parameters in Maya’s UI, from shading to xGen to MASH have randomness built in. You can use sliders to modify those values.” Schönherr says. “This tutorial is more abstract— I demonstrate three random functions, and, noise and sphrand.” Schönherr works with ways to help visualize what the functions are which can help to understand how to employ them.