This is someone starting with id Software's internal level editor for Doom (for NeXTSTEP circa '93), and getting it to build and run on OS X: https://github.com

This is someone starting with id Software's internal level editor for Doom (for NeXTSTEP circa '93), and getting it to build and run on OS X: https://github.com/fragglet/DoomEd/compare/b5885d42226568b18449687853e65cb46ddbea21...master https://github.com/fragglet/DoomEd/compare/b5885d42226568b18... There are a few takes on this out there, same for QuakeEd.