Main site: http://kristianduske.com/trenchbroom/ Youtube basics tutorial: http://youtu.be/Wr9FR1W1JFE So someone made a new open-source editor for quake 1 (yes that game that was released in 1996). The "normal" editor Worldcraft is basically the Hammer we all know, very little has changed in the editing of source/idTech1 engine maps this millennium. It's the same program but with more features added on with time. However, TrenchBroom as I said is new, and the most surprising thing it does is throw away all 2d views, and auto corrects invalid brushes, adds three-point clipping and probably some other stuff. It still produces quake maps, with quake engine limitations, so it's not going to amaze people that much (unless you actually have mapped for quake or even goldsrc, then you know how painful it is to only have brushes to make levels with). Features like realtime lighting in-editor is still off-limits to these old engines, no matter how you code the software. Nevertheless, a pretty impressive effort, and some really nice Brush editing tools.