From JohnC:
"This is a NEXTSTEP application, so hardly anyone is going to be able to use the code as is. This is not an OPENSTEP application. It doesn't even use the foundation kit, so porting to gnustep or openstep-solaris/mach/nt would not be trivial."
"This application was really not a very good fit for NEXTSTEP. The display postscript model fundamentally doesn't fit very well with what we need here -- if you run in an 8 bit color mode, the line drawing runs at an ok speed, but the texture view goes half the speed it should as it dithers from 24 bit color down to 8 bit. If you run in 24 bit color mode, you get less screen real estate and significantly slower line drawing as a 3 megabyte XY view is flushed. Sigh. If anyone does actually run this on NEXTSTEP be advised that you want a fast machine."
"QuakeEd is written for NEXTSTEP 3.3, while GnuStep is an implementation of the OPENSTEP spec. I haven't had time to port it to openstep yet, but it looks like it will take a little effort. NeXT has tools in NS 4.0 to help, but it still isn't automatic."