While visual simulation technology has changed dramatically over the past 15 years – faster graphics, computing, networking – the business model behind our industry has remained relatively unchanged. The model that developed when a reasonable computer cost $500,000 is still around when we could be using game consoles at $250 each. There must be a better way. The future of defense training and education is very different from what it is today. The trend will be towards small, low-cost simulators that are readily accessible to trainees because more of them are available. They will be available in distance learning modes as part of curricula and as stand-alone applications. When we look at initiatives in the Navy to transform training and education, we see that there will be literally hundreds of training applications developed for very specific requirements. The current business model is not conducive to this end. The way software is licensed, sold, and supported is based on a “few, expensive� model rather than a “many, inexpensive� model. We describe why open source software is a disruptive technology to the defense training and simulation industry and we outline business models that fit this new paradigm in simulation development. We determined that most of what is currently available in proprietary game engines and visual simulation tools is already available in open source. The problem is that the needed functionality is scattered across many disparate open source projects. The framework we describe is a unifying layer that pulls these individual open source products together into a common API that is also open. The advantages to the customer are numerous and include (1) the availability of all source code for developed applications – maximizing flexibility in future enhancements, (2) utilizing free software and the ability to benefit from a community of developers to keep up with rapidly changing hardware and software, and (3) leveraging a large community of developers for support. We conclude with recommended actions our industry should take to benefit from open source software.