A massive demonic invasion has overwhelmed the Union Aerospace Corporation's Mars Research Facility, leaving only chaos and horror in its wake. As one of only a few survivors, you must fight your way to hell and back against a horde of evil monsters.
This is PDF versions of the Doom 3 Engine Mapping Basics tutorials by BNA from Doom 3 World. Included are: D3W Tutorial Getting started with your first map, D3W Tutorial Connecting two rooms, doors and visportals, D3W Tutorial Pipes, patches, bending them
I know these tutorials, very nice.