The BSP - Quake Engine Game Map File is a map file system being used by a number of game engines, including the Quake series, Half-life series, Fortress, Counter-Strike and more. Use of the BSP file provides a multidimensional functionality to the game, consequentially providing a more real looking experience.
BSP stands for Binary Space Partitioning. This is a technical process in which the intricate polygons are broken down into convex sets. The process allows for three dimensional maps to be rendered quickly and precisely.
BSP Files are comprised of “lumps” which, in simple, are small bits of data that have been grouped together and defined by the header. Some data groups that are in this category include Entities, Nodes, Vertices, Planes, Leaves, Visibility, Faces, etc. BSP maps are rendered in Binary format.
These compilations can be accomplished with .MAP by using tools such as Q3Map2 or Irrlicht. This can also be achieved by using ID software programs.
Due to the fact that BSP files are developed through map editor projects, they are very rarely modified directly. Some BSP map decompilers exist, decompilers like Vmex, Q3Map2, BSP2MAP, and EntSpy, but they normally do not decompile the BSP files accurately.
So basically through the process of one system being developed and upgraded a new use was found for the MAP file technology to enhance game technology. Binary Space Partitioning creates the ability to integrate multidimensional video interfaces for the games. The dynamics of these multidimensional function allows for a more realistic experience for the game user.
Notable Mention: Since Valve's Source Engine originates from the Quake engine, it also uses BSP files for maps. The Source Engine was used for producing such games as Half-Life 2 and Team Fortress 2.