Doom Builder 2.1

Doom Builder is an advanced, revolutionary map editor for Doom and games based on the Doom engine, such as Heretic, Hexen and Strife. This editor is highly extendible for the different game engines of the Doom community. Doom Builder introduced the 3D editing mode in the Doom community and is still the leading editor for Doom levels today. See the screenshots page for a quick look at this editor or see the downloads page for the real deal. You can find extensions at the plugins page.