G4 and ROOT Frameworks G4 UI

delivering of commands to objects in G4 is ensured by messengers (messenger = an instance of a class derived from G4UImessenger, it is associated with the object that the commands are addressed to)
besides the commands already provided by G4 a user can implement his own commands
the commands
- have powerful type and range checking
- can be state sensitive (will not be accepted in case G4 is not in the state that the command is applicable for)
- can provide guidance
GUIs available (Xo)

delivering of commands to objects in G4 is ensured by messengers (messenger = an instance of a class derived from G4UImessenger, it is associated with the object that the commands are addressed to)