Once the simulator is started (moving to the simulator directory and typing sim in the command line) three window appear in the screen (see figure 2.1).
The largest window is the robot display window. This window shows the view of a camera looking to the world in which the robot is supposed to move. The robot display window includes the ground (the large square inside the window) that in the example figure is a flat surface, the robot (in the middle of the window), and, optionally, a set of landmarks (the small balls around the robot). Initially the camera show a top view of the world and the robot, including all the ground. This can suppose to draw a very small robot (some times almost invisible) if the ground is large. The position of the camera can be changed using a set of tools described below.
The other two windows displayed at start up are the simulator main panel (described below) and the robot camera window. Of course, this last one is only displayed if the robot is equipped with a camera. The position of this camera with respect to the robot is defined in the robot configuration file and its orientation (pan and tilt) can be changed either from the user controller or from the on-line interface.
![\begin{figure}
\centerline{
\includegraphics [width=0.9\linewidth]{images/general.eps}
}\end{figure}](img4.gif)