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As a result, much of the compilation process is no longer required - VBSP, VVIS and VRAD have been replaced by Resource Compiler. The compilation process in Hammer 5 has been simplified drastically, due to Source 2's use of on-the-fly visibility calculation and a deferred lighting model. In 4.0, this has been merged with vbsp.exe. Versions 3.5 and earlier included an additional program, qcsg.exe, which renders the basic outline of the map for vbsp.exe to fill in.
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exe programs vbsp.exe, which renders the geometry, vvis.exe, which renders what geometry appears where, and vrad.exe, which renders the lighting. To do this, Hammer runs the map through three (four in 3.5 and earlier). Hammer can also be used to compile maps so that they can be played in a game. fgd files for official Valve games using the Source engine already come prepackaged into Hammer with the Source SDK, but for the GoldSrc games, the user must add them manually.
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This file tells Hammer what entities the game uses so that it will let the user select them. In order to create a map for a certain game, Hammer must have a special file, called a. Those that create maps for GoldSrc usually use version 3.5, which is the last version that only supports GoldSrc games. However, placing an entity used in only one engine can cause errors. The current version of Hammer, 4.0, supports both Source engine and GoldSrc games. It can also be used to script events in maps, such as Overwatch Soldiers ambushing the player, via manipulation of entities. It is used to create geometry and to place objects (entities) in the game world.
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The Hammer editor is used by level designers to create new maps for Source-based games.
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