Valve Source SDK is a software development kit or SDK software, which is created by Valve Software, that is designed to create mods and maps for Source engine, except for some game applications like Portal 2, Left Dead, and Alien Swarm, as they have their own SDKs already. Source SDK has four main utilities and these are to create a mod, refresh SDK content, reset and edit game configurations. In creating a mod, it dumps the code of Source engine into a folder and a mod directory is created under the folder called SourceMods. SDK content is refreshed by checking new data updates as well as downloads. Game configurations can be reset and edited too. Basic games are the basis of how game configurations are recreated, while mods in configurations are removed except if they are edited manually. There are also applications integrated in this kit software, which are Face Poser, Valve Hammer Editor or Hammer and Model Viewer.
Valve Hammer Editor is a map creation software for games, engines and other sources of Valve Software, This is also called as Hammer, which was more popular as Worldcraft, its original name, that is developed and launched in the year 1996. This is downloadable for any source based game that is part of source SDK or a first person shooter game. Before the Source engine, brushes, which are a set of simple primitives, were the only construction blocks in Hammer Editor, but still usable in older versions of GoldSrc games. This software saves a level life in many format types, which include in the binary and proprietary, text based or .rmf format, human readable .map format, and .vmf format, which was the default level life on version 4.0 and considered a simple file but contains complete information about a level. Furthermore, a level is pass through a program called bsp that uses brushes in order to create the architecture of a level and places entities for the location of a level file. Then, it passes through Visible Information Set or VIS processor, then through the rad program.