The Benefield Anechoic Facility (BAF), located at Edwards Air Force Base, is the world's largest anechoic chamber. Test requirements at the BAF have increased in complexity with the development of sophisticated manned and unmanned systems; as a result, ways to improve existing test methods are important. A “Virtual BAF” 3D modeling and simulation tool is proposed to be used to assess test set up and produce simulation model results. This Virtual BAF simulation tool is a software model of the anechoic chamber and uses the uniform theory of diffraction to predict the RF field environment in the BAF. The Virtual BAF 3D computer simulation model uses Remcom's XGtd ray-tracing electromagnetic simulation software to provide a preliminary RF analysis of test setup. This paper presents the major components of the “Virtual BAF” simulation model as well as a few examples of its use in preliminary test design and setup.