| Arbitrator | Basically, this is a thread of execution in the Simulator most likely a robot, or set of robots |
| Entity | An entity is an object that exists in a workspace, such as a robot, or roadmap |
| IO_Event | Window event |
| IO_Key | Key press |
| IO_Position | Mouse position |
| IO_Window | An OpenGL window with associated input mechanisms |
| MenuEvent | Menu events |
| Path | Three dimensional path in space |
| Path::Point | Estimate of a sample on a path |
| Path::Samples | All relevant path data; in a struct to make reference counting easier |
| Simulation | Keeps track of all of the simulation level stuff Deals with scheduling the entire simulation. Robot's time to calculate stuff, rendering, and user input. Basically this is like "main" for everything |
| Texture | A texture |
| Timer | Abstract timer interface |