This chapter will discuss three kinds of displays (Caves, Walls and Head-mounted) and the external input devices that are used to navigate these displays.

A Cave Environment is an immersive display with one or more screens often arranged in a fashion to give the illusion of being in a virtual space, where you can walk into and look inside of your simulation. The user's head position and orientation are tracked, and the screens are continuously redrawn, to maintain this illusion.

Wall Displays are an arrangement of flat tiled displays with multiple screens, usually rendered using multiple machines. Walls can have a very high aggregate resolution, with a width and height of tens of thousands of pixels. They are commonly referred to as display walls, tiled displays, or power walls.

Head-Mounted Displays simulate a virtual environment much the same as a Cave, except that the screens are mounted in front of the users eyes instead of fixed to the walls.

Finally this chapter will discuss external input devices such as game controllers that improve upon the traditional keyboard and mouse interface for navigation within these custom environments, such as the SpaceNavigator and Gamepad devices.