Question: I want to have a better 3D-view output
       than through screen-grabbing! There is this CELL driver.
       But how to get an output D_cell file when using d.3d? 

Answer: Yes, it is possible - but you have
       strictly to follow this procedure...

Here we go:

1. Create a d.3d view-parameter file:
        d.mon x0
        d.3d
          -> set parameters: viewpoint etc.
          -> store in 3D file when leaving
        d.mon stop=x0

2. Create the D_cell file:

   a) Set the D_cell file size (the size-number must be 1 more 
                                than resulting size):
        export GRASS_HEIGHT=1001
        export GRASS_WIDTH=1201

   b) Start the CELL driver:
        d.mon CELL;d.mon select=CELL
        Wait for "Ready". That may take some time depending on the CELL
        driver size you selected in 2.a). The CELL file must be created
        of that size, in above example it is  1.2MB to be allocated.
         
        d.3d 
          -> specify colormap 
          -> specify elevationmap 
          -> specify 3D parameter file
               - RUN: Y
               - RUN: N (to leave)
          -> save 3Dfile: return (we donīt need saving)

   c) Stop the CELL driver (now the D_cell file is written)
        d.mon stop=CELL
      This may also take time, please watch the CPU-load.
      Only after that you are able to export or use the D_cell file.
     
   e) Set the region to the CELL file (which is in different
      projection):
        g.region rast=D_cell

   f) Export the result (you may also use r.out.tga etc.):
        r.out.tiff -v [-p] in=D_cell out=testoutput.tif
           
      (you may try to use this D_cell file also in ps.map etc.)

   g) Reset the region to original projection:
        g.region -d

   h) Look at the result (use your image program):
        xv testoutput.tif

Have fun.

Markus Neteler/ Michel Wurtz
9. September 1998