What is sub-surface scattering?
It is the indirect transmission of light as it passes through a turbid medium. Things like wax, plant leaves, certain types of plastic, skin, to an extent one could think of sub surface scattering occurring in all living creatures to some degree, as well as a few man made materials....

This tutorial was created by the Florence Design Academy .

On the F.D.A. gallery ( http://www.florencedesignacadem y.com/gallery_eng.html ) you can see a few examples of designs of our students who have used this technique.Since our students need a effective way to display their concepts and ideas, our teachers have developed many tutorials in order to give them an additional tool that every designer should have.This tutorial explains all steps to illuminate an object with a technique which simulates the illumination techniques of a photo studio.Before we begin it is very important to inform you that we will use "Mental Ray" as render engine (version 8 and 9 of 3D Studio Max).

This document provides information on writing procedural texture shaders for mental ray and Softimage|XSI, and is a port of my favorite shader writing resource, the RManNotes by Steve May. As a port these notes are very similar to the RManNotes, and provide the same great general shader writing approach as described there, only for users of mental ray.

The process of rendering, or generating an image in a 3D graphics program, involves firing out rays from a 3D camera and then tracking what the rays hit, one ray at a time. Such rays are fired atleast once for every pixel that is to be rendered on an image.