First steps :
  -----------
  Click in 'Geant4/init' to initialize Geant4
 for this example. This execute the script :
    <package>/<version>/scripts/Geant4/init.g4m

  Note that any action in the GUI triggers interpreted
 scripts (Python, Geant4 intercoms,...)

  Click in 'Geant4/Detector' to visualize some geometry.
 
  Click in 'Geant4/Geant4/Run...' to map the Run dialog box.
  
  Click in Apply to start a run.

  After each event, control is given to the GUI.
 Someone can play with the Inventor viewer controls
 to manipulate the scene.

  Click in 'Geant4/Geant4/Next evt' to return to Geant4 
 to produce a new event.

  By default, the command prompt is set to Geant4
 commands. Try for example :
    G4> /gun/direction 1 0 0
 to change the "gun" direction.   

  Geometry viewing :
  ----------------
  Click in 'Tree/PVs' to display the geometry
 hierachy in the tree widget (the one at the
 left of the viewer).

  Choose an item in the tree to visualize it.

  Using trajectories timed mode :
  -----------------------------
  To change time slicing of the trajectories :

    Python> node = region_findSoG4Trajectories()
    Python> node.set('timeInterval 0.05')
    Python> node.set('timeSteps 200')
    Python> node.set('timeStart 0')

  To have some traceback :

    Python> node.set('verbose TRUE')

  To see current values :

    Python> iv_dumpNode(node)