A small team of engineers and subject matter experts at Lockheed Martin Information Systems has recently completed a Domain Analysis focused on constructive simulations used in both command and staff training (CAST) systems and command, control, communication, computer, and intelligence (C4I) stimulation systems. The intent of the domain analysis was to collect typical requirements for such systems and identify a common set of requirements that could be used to drive the development of a framework and toolset to facilitate future development of systems in the domain. This paper describes the results of that domain analysis. Specifically, it highlights the effort to sufficiently abstract and level the requirements to define the constructive simulation framework and toolset and it identifies the areas in which the currently recognized requirements are weak or missing.