A virtual reality system for use with law enforcement training is described. Simulation software receives a selection of a base scenario layout from a first user and an action associated with a parameter of the scenario to modify the scenario. The simulation software transmits the modified scenario to a user interface of a head-mounted display worn by a second user freely roaming a physical environment of the virtual reality system. The physical environment is defined at least partially by a physical coordinate system. The simulation software receives position data associated with an object and captured by one or more cameras within the physical environment, determines a position of the object from the position data, generates a virtual reality image of the object, adds the virtual reality image of the object into the modified scenario, and transmits the updated scenario to the user interface of the head-mounted display.