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In this report, we describe tools for the creation and modification of modular semi-autonomous forces (ModSAF) terrain databases to support the evaluation of a small autonomous robot in a tactical scenario. Our work is motivated by the modeling and simulation needs of the Demo 3 robotics program which is developing a small tactical robot called the experimental unmanned vehicle (XUV). The XUV is a small wheeled robot which must autonomously navigate through its environment. The primary mission of the XUV will be to augment the scout forces, so it must provide reconnaissance, surveillance, and target acquisition information (RSTA) to its operators. Modeling the XUV in a simulated environment is challenging since existing terrain databases do not have sufficient resolution to examine the mobility characteristics of small vehicles. Our tools increase the resolution and detail of existing terrain databases so that the databases have sufficient detail to challenge the mobility, chassis dynamics, and RSTA models of a small unmanned platform. To properly model a small vehicle such as the XUV, the terrain database in ModSAF needs to be modified. The modification is done in two phases. In the first phase, the resolution of the grid underlying the terrain is increased by placing additional elevation grid posts between the existing posts. Elevations are assigned to the new grid posts using mathematical terrain models such as the variable resolution terrain Model. The new, higher resolution terrain directly affects the vehicle dynamics and the line of sight algorithms. The new terrain does not directly affect the ModSAF route planning algorithms. In the second phase of our terrain database modifications, the slopes on the new terrain are examined. Regions that are steep or inaccessible to the XUV are marked as obstacles in the database.