1. STATUS OF GDML SUPPORT IN ROOT A.Gheata SFT group meeting, June 2, 2014

2. WHAT IS GDML?  Geometry Description Markup Language  Application-independent geometry description format based on XML  GEANT4 geometry persistent format  Evolved in parallel with G4 geometry  Latest release: GDML_3_1_0 from December 2013  Initially developed by several people (mainly R. Chytracek and W. Pokorsky), now maintained by Witold  XML schema + bindings with GEANT4 and ROOT  G4 binding integrated in the toolkit since version 9.2  Built optionally: XERCESROOT variable pointing to XercesC parser library, G4LIB_BUILD_GDML=1  ROOT binding integrated in $ROOTSYS/geom/gdml  Automatic TGeoManager::Export(“.gdml”), but requires configuring with: --enable-gdml

3. SUPPORT IN ROOT  GDML as exchange format between GEANT4 and ROOT geometries  Geometries are alike, the common denominator schema to be supported  GDML parser (C++) + writer (Python script)  Ben Lloyd + Witold, end 2006  TGDMLWrite C++ class re-written  Anton Pytel, Nov. 2011  Including several fixes and improvements  Other contributors  D. Kruse, A.Gheata – ellipsoid support  A. Gheata – support for isotopes  Several people cotributed with fixes

4. MISSING FEATURES  Usage of constants and variables  and keywords ignored not understood  Usage of loops, used to make geometry definition readable and less tedious   Usage of xml nodes across different files (ENTITY statement)  E.g. materials definition or different detectors in separate file  Some of the geometry solids or features which are not supported by ROOT  Would require the development of the ROOT correspondents  User requests  Long-standing ROOT-3347: GDML - constants, multiple files, fraction, unexpected end of file & ENTITY  Recent requests on roottalk

5. OPEN TO DISCUSSION  Approach  To fix: start from existing G4GDMLParser and introduce support for existing GDML schema in TGDMLParse (where possible)  To continue: synchronize adoption of new developments in ROOT  Coordination between ROOT and GEANT4 projects  Timeline  This is rather urgent since it blocks several people in using ROOT geometry features (graphics, checker, event display, …) when starting from a more advanced GDML description.  1-2 months ?  Resources  I can contribute only partially due to priorities in other projects  Summer student (rather late now), part of the work of a technical student?