Is there any script that vertex paints a vertex according to it’s altitude (z position)?
well, not really but there are a couple of ways to do it.
1 load a colored gradient into the UV editor window, then looking at your model from the front or side, load it into the UV editor ( go into face select with F key, the use U key to load selected faces ) choose ‘from window’ from the mapping menu that will pop up when you press U, then when your faces are loaded into the UV editor, scale them ( s key ) and/or move them, until they are about how you’d like them…the other way,…
2 instead of loading the image into the UV editor, click on ‘view’ buttons and load it as a background image. go into front or side view, and give your object a material with the image as a texture, and change mapping from ‘orco’ to ‘win’. then, in edit buttons, press ‘sticky make’, and in material buttons click the mapping from win to ‘stick’.
<edit> oh and of course before sticking it, adjust your object, position.scale-wise, so that the image falls where you want it.
<edit> oh and one more step,…set material to shadeless, and press V to activate vertex colors, press V again to toggle out of vertex paint mode, and press ( in edit buttons ) ‘vertex color make’. Then in materials, press vcolor. I hope I got all of this stuff right, just come back if it isn’t. <edit> Oh, and shadeless was just for when we made the vcolor, so you can toggle that off.