hi, thanks you for the replys and @GecT, the tuts are awesome, I will use them..

But now I´m a little bit further in depth with this problem.

below you see the first pic which is made with maya software which has rendered pretty well, what I´m looking for!
Perfecto the fractal is a good idea, but how you see I wantet that effekt through real geometry! in that case a tree.
and that light and fog penetrated through the tree gives a nice atmosphere, for what my efforts are!

It were to nice if there wasn´t one problem!
the second image shows the same scene rendered with mental ray and the disturbed render. the tree is converted to a mesh, that MR can read and setting aren´t responsible for that "mistake" ! I tryed out the settings...

What could we do to render that with mental ray, because the final scene includes FG GI SunSKy.

hope I explained everything fine and you can follow my vision for that aniamtion...

It must get finished, I will!!!