A collision avoidance system for an unmanned aerial vehicle (UAV) receives physical space data for a flight area and creates a virtual world model to represent the flight area by mapping the physical space data with a physics engine. The automatic collision avoidance system creates a virtual UAV model to represent the UAV in the virtual world model. The automatic collision avoidance system receives flight data for the UAV and determines a current position of the virtual UAV model within the virtual world model. The automatic collision avoidance system determines a predicted trajectory of the virtual UAV model within the virtual world model, and determines whether the predicted trajectory will result in a collision of the virtual UAV model with the virtual world model. The automatic collision avoidance system performs evasive actions by the UAV, in response to determining that the predicted trajectory will result in a collision.