- The main article for this category is Eternity Engine.
“The Eternity Engine is a GPL source port maintained by James "Quasar" Haley and Stephen "SoM...Eternity Engine
“MAPINFO is a lump introduced in Hexen which allows to describe meta-data associated to levels...MAPINFO
“A 3D middle texture, often abridged as 3dMidTex, is a sort of simplified 3D floor without a...3D middle texture
“Slopes are an editing feature supported by some Doom source ports which allows the designer to...Slope
“Skyboxes are different methods by which a fully 3D sky can be constructed (instead of the...Skybox
“Portals allow a map to have a geometry not normally possible in a "2.5D" engine such as Doom. A...Portal