Map unit

The positions and sizes of objects in Doom levels are generally described by integer values between -32768 and +32767. The unit length is often called a map unit (or simply, unit). Some example dimensions in terms of Doom's map units are:
 * 24 = 16 units: small map details such as support beams and wall lamps
 * 25 = 32 units: smallest gap the player can pass through
 * 26 = 64 units: regular crate, small teleporter gate
 * 27 = 128 units: big door, width of regular corridor such as the main hallway in MAP01: Entryway (Doom II)
 * 200-400 units: width of a small room
 * 500-800 units: width of a medium-size room, such as the start room of E1M1: Hangar (Doom)
 * 768 units: width of the Icon of Sin
 * 800-1500 units: width of a large room such as the Spider Mastermind room in MAP06: The Crusher (Doom II)
 * 4000 units: width of typical Doom level (Knee-Deep in the Dead)

It is difficult to translate the size of a Doom map unit into a real-world unit, since the dimensions of various objects in the game are inconsistent. Very roughly, one could attempt to translate 32 map units as 1 meter (3.28 feet) based on the height of the Doom guy (56 units). With this interpretation, a Cyberdemon would be 3.5 meters (11.48 feet) tall and a typical Doom level would have a size of approximately 120 m &times; 120 m (393.7 ft &times; 393.7 ft).

However, height and width units do not quite agree. The 1-meter interpretation would imply that the Doom guy is one meter wide, or at least cannot pass through an opening narrower than one meter, which would be to exaggerate his muscularity. The discrepancy is likely related to the fact that pixels in the video mode Doom ran in were rectangular: because pixels were higher than they were wide, and each map unit was proportional in size to a pixel of an in-game texture, flat, or sprite, height units were larger than width units. A more realistic interpretation (if there is any such thing) is perhaps that one "width unit" (w) corresponds to 3/4 of a "height unit" (h).