The requirements for acceptable visual presentations by simulation techniques for use in training pilots and other vehicle operators are defined. These are defined in terms of the human operator's visual capabilities. Among the requirements to be discussed are: the field of view, necessary detail, light level of the picture, performance characteristics of the flight simulator or other vehicle simulated which are important to a visual display/simulator combination, requirements for specific missions, and simulator per-formance. The second portion of the paper will describe some visual simulation techniques and research hardware developed to date. The compromises and limitations of the equipment as well as advantages of various techniques will be discussed. The visual simulation techniques to be covered will include the shadowgraph/point light source, television, and optical techniques for providing clear day or low visibility conditions.