In recent years, we have come to realize that physiological motion cues are but one part of a total simulation experience. It must be augmented by the "visual" cue which appears to have become accepted as the more important aspect of the two. In the past, we have seen a transition of Visual System techniques from Film Projection to Terrain Model Boards with current enthusiasm for Computer Generated Image Systems. In the competitive struggle for increased realism, the COMPUTROL Computer Generated Image System has come of age due to its ability to dynamically change scene content in real-time. Not only is there freedom of eye movement around a particular CGI model, but also the capability to effect a "complete" change of gaming area in reasonable time. The goal of our research and development efforts has been to incorporate current "chip" technology, resulting in a new computer design capable of highspeed data handling. The objective was to create a full-color raster scan simulation of a three-dimensional real world. We recognize that the product of our research and development efforts should match the following criteria.

Resolution and fidelity of the final scene should closely equate to that of optical or high-quality film systems.

Minimal power requirements for economical operation.

Inherent capability to quickly change entire gaming areas.

Gaming data size sufficient to permit extended flight simulation without reaching the limit of stored data.

High-speed computation to permit dynamic movement of objects within the displayed scene, e.g. moving vehicle (land, sea, or airborne).

System design sophistication to permit miniaturization of the entire system.

Reasonable purchase price and cost of ownership. Affordable by a majority of customers.

We feel confident that our research efforts have met these seven basic criteria. A 16,000 edge full-color static demonstrator has been developed. Capability to generate high-definition pictures with variable sun angle, smooth shading, and the occultation of hidden surfaces has been proven. Occulting of objects through the visible edge solution guarantees nonbleed through of hidden lines. Another feature of the COMPUTROL, windows look like windows rather than holes in buildings. The transition to and from clouds is also much more convincing.

System architecture and special algorithms are used to permit the incorporation of texturing with respect to trees, grass, clouds, and water. The key ingredient of the system design is the "atom" philosophy of geometric forms used as building blocks for the total scene model. The basic forms are stretched, squashed, lengthened and/or added to other geometric forms to develop a particular scene. The modeling and use of atoms is performed in the off-line mode where there is the ability to generate and modify scenes as well as to edit and assemble programs. With the exception of flight data or any other vehicle interface which is resident within a simulator "host computer," the visual system is a self-contained digital image generator with bulk storage of specific geographic areas. The current design has the capability of displaying 30,000 edges. The surfaces can be planer or spherical due to the systems' ability to smooth-shade curved surfaces. There is virtually no limit to the number of edges that can be contained within the gaming area data base. The special-purpose CPU used with the image generation system has been especially developed to provide the computational speed necessary within the total system. Risk normally associated with a specially designed computer system has been substantially reduced due to the use of standard MOS chips and straight-forward computer architecture. The resulting CGI technology promises to set the standard for visual simulators for many years to come.