The Brazil Rio Render System from Splutterfish, LLC (www.splutterfish.com) like its retail version comes with many great shaders to improve your renders. However, unlike the full retail version, there is not much help in the way of tutorials for the Rio version. There have been some done by other users, but none for the skin shader in particular. In the following tutorial, I will show you how easy it is to achieve very desirable results.
The above image is the result of some tweaking of what I learned in the Mental Ray SSS shader and after some trial and error translation over to Brazil, was able to achieve very nice results. The only real downside is the increased render time. When using a simple material map, my render time for the above image was less than 10 seconds on a P4 2.8 Ghz with 512MB RAM. With SSS on, the image shown, render time increased to 9:34 for a 640x480 image.
As an interesting little side note before we begin: I want to let you know that I originally started out using the Mental Ray Fast SSS skin shader and had found an excellent tutorial online that explained the principles of what we are trying to achieve with Sub Surface Scattering (SSS). This can be found at http://www.lamrug.org/resources/doc/sss-skin-tutorial.pdf. Is strongly suggest you follow this link and read the explanations of the principles of SSS as this will help you to set your shader up a little better.
For this tutorial I will be using Victoria 3 at her default size if you simply import the OBJ directly into MAX. The system units for this (as this is scale dependant) is set to International Generic Units. You can import her and apply the materials however you usually do whether by selecting the individual mat groups and applying the material that way or by using the eyedropper tool and then working with the Multi/Sub Object material. Either way will work fine. I am just showing you how to set up the material itself. The eye, eyelash, eyebrow, and pubic hair mats, I leave to you as they are just simple mats and have not been set up with SSS.
I have not had you set up the render itself yet. We will get to that once we have the material set up. Once this is done, you can tweak it to your liking.