Understanding Hair

Although a section titled "Understanding Hair" sounds like it would be taken from a beauty salon guide, the way Max deals with hair is unique and needs some explanation. Hair, like particle systems, deals with thousands of small items that can bring even the most powerful computer screeching to a halt if not managed.

In Max, hair doesn't exist as geometry, but is applied to scene objects as a separate modifier. This level of separation keeps the hair solution independent of the geometry and makes removing or turning off the hair solution as needed easy. It also keeps the viewport display from bogging down. The Hair and Fur modifier is a World-Space Modifier (WSM), meaning that it is applied using the World Space coordinates instead of local ones.

The other half of the Hair and Fur solution is a render effect that allows the hair to be rendered. This render effect is applied and configured automatically when the Hair and Fur modifier is applied to an object. This causes the scene with hair to be rendered in two passes. The geometry is rendered first, followed by the hair.

Note 

Hair can be rendered only when a Perspective or Camera view is selected. Hair cannot be ren-dered in any of the orthogonal views.

Another similarity to particle systems is that the hair follicles can be replaced by instanced geometry, so you can create a matchstick head character by replacing hairs with an instance of a matchstick.

The materials that are used on hair are defined in the Material Parameters rollout in the Modify panel instead of in the Material Editor. Many of the hair parameters have a square button to their right that lets you apply a map to the parameter.

When the Hair and Fur modifier is added to an object in the scene, a Hair and Fur render element becomes available that you can use to render out just the hair for compositing.