I don't know,
Maya included “help” for me, is not a very useful help

You know, I like study everything by myself.
And help useful for me: first do this; second do this; third do this…
Example from Maya help:
Q: Why PainFX do not work properly with dynamics (or fluid) fog?
A: Use the rendering passes. (I don’t remember exactly answer, but something like this)
But HOW? And where?

(My brother ask my to create nature scene with fog for his desktop)
I try converting PaintFX to poly… a lot of grass and trees… I think you understand what’s happened with my computer.