This paper describes a project which aims to create an authoring environment for simulation-based training in order to illustrate features necessary for: (1) an environment which can be used by teachers/trainers with minimum technical skills; (2) rapid prototyping by all courseware producers; (3) and tools for model building. The paper begins with a section summarizing results of an earlier survey of commercial and educational producers of computer-based training materials. The second section outlines training, authoring, delivery, and development requirements for simulation courseware, and the third section lists overall project requirements. The fourth section describes the current phase of the project, i.e., the production of a demonstration toolkit. Requirements for prototype courseware are summarized in the fifth section, including general requirements, courseware functionality, and assumptions. The sixth section presents prototype model requirements, covering general requirements, typical model components, and the nature of required models. The seventh section lists demonstration phase toolkit requirements, including general requirements, modelling tools, and authoring and learner interface tools. General, modelling, and authoring requirements not addressed by the demonstrator phase are discussed in the eighth section. The appendix includes a description of two courseware products to be produced in the demonstration phase and a list of the abstract properties of model objects. (MES)