3d Game Level Design

The term level is normally used to describe the interiors of building, dungeons or industrial complexes in which many games take place. Levels are different from exteriors in that they typically consist of regular geometry (hallways, staircases, etc.) rather than terrain. Level design tools typically allow the definition of the level's geometry as well as the placement of entities (furniture, monsters, etc.) and light sources.

3ds Max - Windows only; commercial. For those who can afford it, 3ds Max can be used to edit levels.

Blender - Windows, Mac, *nix; free under GPL. Blender is a free modeling tool, with many advanced features and a very active and dedicated community. The GUI need getting used to, but lends itself to a very efficient work style once learned.

GtkRadient - Windows, Linux; Licensing murky. To use GtkRadiant, you require a copy of Quake 3.

Maya - Windows, Mac, *nix; commercial. For those who can afford it, Maya can be used to edit levels.

QuArK - Windows; GPL License. QuArK is another Quake 3-format level editor. Levels are generated in .map format, which must be compiled to BSP format.

WorldCraft/Hammer - Windows; Only to develop new levels for Half-Life and other compatible Valve products. Hammer (called WorldCraft prior to 3.0) was developed as a modding tool for the Quake and Half-Life games. Licensing of Hammer prevents its general use, though I believe the restrictions on earlier versions were weaker (unable to find references at the moment, though I believe WorldCraft was purchased by Valve and renamed to Hammer). WorldCraft generates MAP models which must be compiled to BSP format.