This thesis presents TraJECT-3D (Track and Junction based Exploit over Complex Terrain), a realistic generator of node movement trajectories for simulating tactical Mobile Ad-Hoc Networks (MANETs). TraJECT-3D models the macro- and micromobility of different types of tactical nodes (e.g., soldiers, scouts, unmanned aerial vehicles) with a bidirectional track and junction strategy. The novel aspects and distinguishing features of our mobility model are: (1) supporting a three-dimensional topology which is essential for realistic modeling of tactical scenarios in difficult terrains, and (2) considering variable-size group mobility, multiple mission-based formations, and the inclusion of aerial traffic at the macro-mobility level and correlated movements at the micro-mobility level. TraJECT-3D is validated by illustrating how the interactions between terrain characteristics, macro-mobility and micro-mobility models reproduce typical phenomena of tactical networks. Evaluation results show that the choice of mobility model heavily impacts node movement and density over terrain which in turn has a large impact on the performance of networking protocols.