hi, please excuse me for the response delay
mental ray is using (as renderman and actually any renderer) it's own shaders to render an image.These shaders are something like a *.mi file.
Mental ray for maya is a plug wich will translate the maya scene to a mental ray scene and all the maya shaders to equivalent mental ray shaders.But since mental ray for maya 1.5 you can use mental ray shaders directly within maya . So you can use all the fonctions of these shaders and even write your own.
Mental Ray is using C or C++ languages for its shaders and scenes.With the mental ray realease there are many public shaders provided but these are *.c files and i don't know how to compile them to *.mi files...
I know the theory but nothing about C++ and advanced rendering so i'm trying to learn and it's everything but easy !
You can already use mental ray shaders within maya and i really would like to find a tut about these because i can't do nothing with them.
Hope these few knowledges answer your questions
and please excuse my poor english
toniobe