15.64.59  THREE 

This  sets  parameters  for 3-dimensional plots and turns ON 3-d graphics.
Essentially you must set up the viewpoint for 3-D.  The plot is seen by an
observer  through  a  "screen"  or window.  The location of the screen and
observers eye may be specified.
SET THREE [ON|OFF|AUTOMATIC]]
     [CENTER=x,y,z]
     [VERTICAL=xv,yv,zv]
     [DIRECTION=xv,yv,zv] [THETA=angle] [PHI=angle]
     [DISTANCE|RDISTANCE=n] [SCRD=n]
     [REDUCE|MAGNIFY=n]
     [ORIGIN=x,y,z]
     [SEPARATION=s|LEFT|RIGHT|MIDDLE]
     [WORLD=x [BY] y [BY] z]
     [XAXIS|YAXIS|ZAXIS=angle]
     [PERMANENT]

NOTE:   The  actual  view  also depends on the window size selected by SET
WINDOW.


                                  WARNING

     If  this  command  is  issued in between 2 plots overlaying each
     other, they will not have the same scales.