Hammer-Editor

The Hammer Editor (Or more formally known as the Valve Hammer Editor) is the official mapping tool for the GoldSRC Engine, Source Engine and the Source 2 Engine.

The Splash Image of the Hammer Editor when it's opened.

The Hammer Editor as we know it began its development as a fork of the ID Tech 2 Engine with the name of Worldcraft. However, after Valve adquired the rights to it, it effectually became known as the Hammer Editor. It has been used in every Valve game release excluding Dota 2.

Overview of the Hammer Editor

The Hammer Editor is primarily brush-based aswell as heavily reliant on brush-based entities, such as but not exclusively limited to triggers, moving entities, interactive entities, static entities, dynamic entities aswell as sound-based entities such as ambient_generic and env_soundscape.

An important aspect of the Hammer Editor is its useage of Forge Game Data (FGD's) which includes all of a game's data, compiler options, registered entities, etc. which will tell the engine the paths of every asset location from the game currently being modified. Along the use of FGD's, the Hammer Editor also utilizes an important file called gameinfo.txt which is in charge of stablishing the compiling tools of the Hammer Editor version being used; such as vvis.exe, vrad.exe, vbsp.exe.

Example of a gameinfo.txt file, taken from Garry's Mod files.