So.. perhaps "height field" can be the solution, but I'm a linux user and
can't use MacDem or Dem2POV..
I've found srtm (geotiff converted to png or tga) data ready to use like an
image_map at this link:
http://srtm.csi.cgiar.org/SELECTION/inputcoord.asp
it seems works pretty good..
bye and thank you again..
Alberto.
