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How Virtual Reality Works

Virtual Reality History
Photo courtesy of Atticus Graybill of Virtually Better, Inc.

The concept of virtual reality has been around for decades, even though the public really only became aware of it in the early 1990s. In the mid 1950s, a cinematographer named Morton Heilig envisioned a theatre experience that would stimulate all his audiences’ senses, drawing them in to the stories more effectively. He built a single user console in 1960 called the Sensorama that included a stereoscopic display, fans, odor emitters, stereo speakers and a moving chair. He also invented a head mounted television display designed to let a user watch television in 3-D. Users were passive audiences for the films, but many of Heilig’s concepts would find their way into the VR field.

Philco Corporation engineers developed the first HMD in 1961, called the Headsight. The helmet included a video screen and tracking system, which the engineers linked to a closed circuit camera system. They intended the HMD for use in dangerous situations -- a user could observe a real environment remotely, adjusting the camera angle by turning his head. Bell Laboratories used a similar HMD for helicopter pilots. They linked HMDs to infrared cameras attached to the bottom of helicopters, which allowed pilots to have a clear field of view while flying in the dark.

In 1965, a computer scientist named Ivan Sutherland envisioned what he called the “Ultimate Display.” Using this display, a person could look into a virtual world that would appear as real as the physical world the user lived in. This vision guided almost all the developments within the field of virtual reality. Sutherland’s concept included:

  • A virtual world that appears real to any observer, seen through an HMD and augmented through three-dimensional sound and tactile stimuli
  • A computer that maintains the world model in real time
  • The ability for users to manipulate virtual objects in a realistic, intuitive way

In 1966, Sutherland built an HMD that was tethered to a computer system. The computer provided all the graphics for the display (up to this point, HMDs had only been linked to cameras). He used a suspension system to hold the HMD, as it was far too heavy for a user to support comfortably. The HMD could display images in stereo, giving the illusion of depth, and it could also track the user’s head movements so that the field of view would change appropriately as the user looked around.