Example of a Simple Crowd System

This chapter presents four examples in which a crowd system tool using Maya's solid dynamics system and MEL scripts is created to implement an interface and crowd behavior. The aim is make the tool robust enough for others to use. These examples seek to have a complete procedure that constructs a scene with a number of crowd vehicles that will have their own rules to follow, describing how to interact with other vehicles that can be interactively controlled by the user. The first example deals with making the "vehicle." This vehicle is constructed from a polygonal cube that makes a solid dynamic object so that one can rely on Maya's dynamics engine to compute its motion. The second example looks at how two vehicles will react to each other. For the crowd system, two behaviors are developed where the first behavior establishes each vehicle's tendency to avoid collisions with others, and the other establishes that some of the vehicles, which the script will define as "followers," tend to follow other vehicles, defined as "leaders." The third example adds the ability to turn selected objects into obstacles for the crowd's vehicles. The script is also provided with the ability to add a user-controllable global field that affects all of the objects uniformly.