1. Geometry checking tools Gabriele Cosmo (CERN/IT-API)

2. Outline • Addressing recommendation #3.6: “ The GEANT4 team should provide a basic set of tools to validate complicated detector geometries. These tools should be available to users not only as a set of C++ classes that the end user can access from his own application but also as part of an interactive geometry display package. A minimal set of requirements for interactive capabilities are those provided by interactive GEANT3 ” • An interactive graphical tool for debugging overlapping geometries is provided since 1998 • Additional run-time commands for fast and effective debugging have been made available since release 4.0 and extended in release 4.1 • A new interactive tool for geometry debugging is available in release 4.1 • DTREE commands available since release 4.0 Geant4 delta-review - G.Cosmo, Geometry checking tools

3. DAVID Graphical Tool • Released in 1998 • Allows for precise rendering of complex geometries and possible imperfections • Generates precise debug information to identify overlapping elements • Can be run as a stand-alone application Geant4 delta-review - G.Cosmo, Geometry checking tools

4. Run-time debugging commands • Available since release 4.0, as contribution of the BaBar collaboration • Used in BaBar for the verification of the detailed geometry description of the BaBar detector • Built-in commands to activate verification tests on the user geometry setup • Adopts technique of intersecting solids with linear trajectories • Several pattern algorithms available (single line, recursive grid, cylinder, …) • Precise output produced • Excellent coverage if combined with DAVID Geant4 delta-review - G.Cosmo, Geometry checking tools

5. OLAP tool • Available in release 4.1, contribution of the CMS collaboration • Uses tracking of neutral particles to verify boundary crossing in opposite directions • Stand-alone batch application • Can be combined with a graphical environment and GUI (ex. Qt library) • Integrated in the CMS Iguana Framework Geant4 delta-review - G.Cosmo, Geometry checking tools

6. OLAP tool Geant4 delta-review - G.Cosmo, Geometry checking tools

7. Visualizing detector geometry tree • Built-in commands defined since release 4.0 to display the hierarchical geometry tree • As simple ASCII text structure • Graphical through GUI (combined with GAG) • As XML exportable format • Implemented in the visualization module • As an additional graphics driver • G3 DTREE capabilities provided and more Geant4 delta-review - G.Cosmo, Geometry checking tools

8. Geant4 delta-review - G.Cosmo, Geometry checking tools

9. Conclusions • Interactive graphical tool DAVID for debugging overlapping geometries provided since the first production release in 1998 (defined UR) • BaBar contribution in release 4.0: built-in run-time commands based on linear intersection technique • Set of commands extended in release 4.1 • CMS contribution in release 4.1: OLAP tool for tracking-based debugging • DTREE functionality and commands available since release 4.0 • Future evolutions: • Extend OLAP tool with integrated GUI Qt-based Geant4 delta-review - G.Cosmo, Geometry checking tools