Here is another scene file. The sole purpose is to provide a simple function which hopefully sheds some light on the vector conversion thing. This function, although in this example its applied on a Vue rock, is not meant to create some suitable displacement for rocks. At this point its not even important that it`s connected to the displacement output and is affecting the geometry of the rock.

Everything the nodes do can be observed directly inside the function editor.

So all you need to do is to select the Vue rock and then accessing the function via material editor.

Here is the link to the scene file:
http://www.artmatica.ch/Vue_temp/Numbers-Vectors.zip

Below is a sceenshot of the function along with some explanations.

http://www.eonmusic.ch http://www.artmatica.ch