G4UIRoot is a new GEANT4 GUI built using the ROOT libraries. It fully integrates into Geant4 and brings together the strengths of the GEANT4 user interface and ROOT capabilities. To find the motivations behind this project you may look here.

G4UIRoot provides all the functionality available at the Geant4 command line user interface integrated into a clickable GUI and allowing several ways to interact with your simulation program. Some of the main features you may find in G4UIRoot are:

• The full Geant4 command tree is displayed in a file system like structure. Non available commands are identified and cannot be selected. The availability of the commands is modified whenever Geant4 status changes.

• The command line at the bottom of the GUI allows the user to also type the commands as he would do in a normal terminal session. Selecting a command in the tree will automatically update the command line input widget with the full command path and vice-versa. Automatic command completion using the TAB key is supported. The navigation through the successful commands executed before may be done using the arrow keys.

• Different windows for normal and error output with saving capabilities.

• History window with saving capabilities. History is tracked even if the window is closed. Successful commands may be recalled at any point by simply hitting the up arrow at the command line.

• Full command help shown. Short command help shown in pop up messages and in the status bar.

• Possibility to execute Geant4 external macros directly from the menu.

• Customizable main window title and pictures.

• Direct access to Root TBrowser.

• Root interpreter (CINT) included. It runs in the terminal.

The last couple of points may allow in the future, when Geant4 is rootified, a direct inspection of Geant4 classes and objects (at run time) and direct access to Geant4 code (again at run time).

For instructions on how to download and install G4UIRoot and how to compile your program to use it see the installation page.

I would like to thank Jacek M. Holeczek who has spent part of his time testing, correcting and improving this GUI. The modifications to the examples and many interesting functionalities come from his ideas. I would like to thank also the ALICE collaboration for their support on this project. I should also mention GAG whose look and feel inspired this GUI.