What? Where? Production shaders?
Well, here's the story:
The Hidden Shaders
If you have installed 3ds Max or Maya 2008, you will have obtained mental ray 3.6, and with mental ray 3.6 comes the production shader library.
However, in neither of Max or Maya are these shaders exposed by default to the end user. They are hidden, and therefore "unsupported".
Still, they are there, and they can be used. But to do so, one must first "unhide" the shaders.
Simple matter of resources of Quality Assurance at Autodesk. The shaders has not gone through enough torture - yet - to be signed off by QA as "officially supported". But that's where you, my adventurous mental ray addict, come in! Consider this an extremely public beta, if you will....
How do I "unhide" them?
Unhide instructions for 3ds Max 2008 are here
Unhide instructions for Maya 2008 are here
What are they
The production shader library is a set of tools, some simple, some complex, to aid in doing production rendering, i.e. in a visual effects context.
There are two basic categories of shaders:
First we have the simple utilities like applying a gamma to a color, or giving different results for different "ray types" (reflection rays, transparency rays etc.). These shaders are very simple, and you probably have found similar shaders online before. These shaders are not better than those other shaders that do the same thing, they are simply a standard set that now ship with all products. I.e. "mip_rayswitch" isn't terribly different to Control Studio's "ctrl_rays", but you don't have to install anything to use it.
Then we have the more complex shaders, such as the 2.5d motion blur shader, or the matte/shadow/reflection system used to cast shadows (and reflections) off of a stand-in object in your scene, for integrating CG objects into a background plate.
A lot of examples of the mip_matteshadow and other production shaders are available as a small demo movie constructed for siggraph, it's available as YouTube as well as WMV, QuickTime and DivX versions.
What do they do?
The main intent is to simplify the workflow of compositing CG objects into background plates, and other visual-effects related tasks that one may run in to on a daily basis.
In some cases they exist to give a simple workflow to a simple thing. For example, the mip_cameramap is a simple camera mapping shader that simply projects back an image from the render camera (and only that camera) "into" the scene 3-dimensionally (unlike, say, mib_lookup_background, Max's "Screen" mapping, or similar).
There are more complex "camera projection" shaders out there both for Maya and Max that can do similar jobs, but at a slightly higher effort. Again, the logic here is to provide the simple tool that can do the job, and if you need the more advanced feature, use the more advanced feature.
Similarily, the mip_mirrorball shader is for a simple unwrap of a mirror ball into an environment map when taken from the same camera angle as the background plate. For anything more advanced you would probably have to unwrap the mirror ball image in some unwrapping software and apply as a spherical map... or maybe you are a high-end user that uses SpherOn cameras and don't even use mirror balls... then ignore this shader, use your more powerful tools.
Mark my words, I will be posting quite a lot on the topic in the months to come, but meanwhile you can read the PDF documentation. In Max, the names of the shaders will appear slightly different than in the manual, but you can figure that our rather quickly, I hope.
That's all I have time for for for now:
Stay tuned to future blog posts on the subject.