15.72.17  3-d 

If the options  X,Y,  or  Z  are  used,  then  the  title  is  plotted  in
perspective  relative  to the default X,Y,Z axis.  If you set each axis to
be in  a  particular  location,  then  you  should  plot  the  axis  title
specifying  X,Y,Z  or specify the origin using the SET THREE command.  The
title starts at the origin of the axis.  If the option CENTER is used  the
title is centered along the axis.

If  the  title  position  is  also  specified,  then  the title is plotted
according to the position specified.

The  AXIS  angle determines the orientation of the title.  See the command
SET THREE.

If  a title is drawn in perspective, subsequent title commands without any
position specifications will draw more titles above  or  below  the  first
one.  The displacement is picked away from the axis.