World Editor

Pics of the the Quake Wars World Editor.

Doom 3's Radiant provided a major improvement over its predecessors: level designers could simply press a key to see exactly what your world would look like in the game. editWorld takes this great time-saving ability and extends it to include real-time preview of the MegaTexture, sunlight, ambient lighting (for setting mood and filling out dark corners in rooms) and atmospheric effects like haze and clouds. Some designers work almost exclusively in this view (called Render mode).

Quote taken from Splash Damage Dev Diary #5.