The DISPLAY variable must be set for GPHIGS, as for any X11 client.
Example:
On UNIX systems
setenv DISPLAY unix:0.0
On VMS systems
set DISPLAY/create/node=<hostname>
In addition, the same application may open several workstations on several different servers. Simply specify the DISPLAY associated with a workstation (%dx) in the configuration file. In this case, the DISPLAY variable is ignored.
For instance to redirect display to the star host, add the following line to the configuration file:
%dp star:0.0