3D View is a MAPSGAP tool that provides an external view of the target body system.  During tour, for example, 3D View provides an external view of the Saturn system, including Cassini.  The Cassini trajectory and satellite trajectories are drawn, providing a nice graphical way of visualizing a segment of the tour.  Times of interest can be found quickly by clicking on the Cassini trajectory.  3D View will automatically update the plot to the desired time and display that time in the plot.  You can then copy this time into the Session Data Entry Widget for use with Skymap or Target.  Opening 3D View after a session has already been started with Target or Skymap will automatically open it with the display for the same time and target body as was selected for those tools.
 

For more information about the 3D View tool and the Track tool, see the MAPSGAP User's Guide.