Abstract - Most current training simulation systems employ custom generated, ad hoc approaches to building terrain models. Recently, the DARPA STOW Worldwide Terrain Database generation effort, the Joint Simulation System (JSIMS) Synthetic Natural Environment (SNE), and the Joint Warfighting Simulation (JWARS) SNE have cooperatively defined a Terrain Common Data Model (TCDM) for low and medium resolution simulations. The U.S. Army STRICOM Synthetic Natural Environment Science and Technology Objective (SNE STO) seeks to extend the TCDM to other important classes of simulations, thus improving overall interoperability between networked simulation, as well as defining the basis for terrain data production requirements, terrain integration constraints and expectations, SEDRIS transmittal contents, and runtime terrain data use. At IST, our efforts are concentrated on extending the TCDM to low-cost visual systems. Our approach is to develop a detailed specification of terrain database requirements based on tasks commonly performed using low-cost visual systems. In this paper, we chart a course for accomplishing this goal, including describing the development of a structured database of design elements, the definition of a multi-systems view to include multiple resolutions and sensors, a plan for being consistent with initiatives by others working on the TCDM, and our plans for future work in this area.