As I was building a very large map recently in vanilla Doom, I kept bumping into the various limits of the map format, and being a newbie took some time to work out what the actual limit was, and how to address each one. While the information is out there, I couldn't find it all in one place, so in the name of helping other people in the future, here's a compilation of what I learned are the typical limits you're going to reach as you expand the geometry of a map, and what's require