Realistic simulations of the movement of infantry in urban environments with 3D models and at interactive rates is of wide and enduring interest. Many video games have attempted it, and military simulations are increasingly doing the same. Previous attempts have fallen short in two areas: properly coordinating movement, and adequate modeling of the detection of hostile targets. Novel algorithms to simulate fireteam movement and visual scanning appropriate to urban environments are described. Measurements of the computational performance of the most expensive components of the approach are provided.