True, but Duke Nukem 3D did the same thing (actually, id didn't release any tooling for Doom: id's internal DoomEd was written in Objective-C for NeXT machines, so it wouldn't have been much use in any case. They didn't start releasing their internal design tools until a bit later, meaning that DN3D did it first), and DN3D's community is virtually dead, while Doom's continues to thrive.