In this thesis, we develop two new methods for simulating large, dense crowds. We consider crowds of
several thousand agents. Each of these agents has to navigate the scene to reach its goal, while avoiding collisions with obstacles and other agents. Thus, our simulation methods must be able to solve two separate tasks. Firstly, they must enable agents to find a path from their current locations to their goals. Secondly, they must ensure that the agents can avoid obstacles and other agents while moving towards their goals.