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Taming Geant4 Verbosity

G4/Op Integration Overview


Full geometry Geant4 and Opticks integrated, enabling:

  • full geometry testing/development/comparison
  • Geant4 particle gun control from within interactive Opticks (GGeoView)
  • operational without CUDA capable GPU, using Geant4 simulation and OpenGL viz
  • drastically faster operation when have CUDA capable GPU

See Also

  • cfg4- partial integration for small test geometries only
  • export- geometry exporter


Geant4 and Opticks need to be using the same geometry...

  • G4DAE for Opticks
  • GDML for Geant4

Standard export- controlled geometry exports include the .gdml and .dae when they have a “G” and “D” in the path like the current standard:



  • OpticksResource .gdml path handling
  • Break off a CG4 singleton class from cfg4- to hold common G4 components, runmanager etc..
  • move ggv- tests out of ggeoview- into separate .bash, check the cfg4 tests following refactor
  • add GDML loading
  • workaround lack of MPT in ancient g4 GDML export by converting from the G4DAE export
  • collect other(non-photon producing processes) particle step tree into nopstep buffers
  • split G4 geometry handling into TEST and FULL using a CDetector based specialized with:
    • CTestDetector for simple partial geometries
    • CGDMLDetector for full GDML loaded geometries
  • pmt test broken by g4gun generalizations, fixed up to the groupvel issue
  • CPU indexing, to support non-CUDA capable nodes


  • nopstep visualization


  • workout where/how best to do the with/without CUDA split,
    • currently done very coarsely in App with preprocessor macro WITH_OPTIX
  • where to slot in CG4/CGDMLDetector into the machinery, cli, options, config ?
    • ggv-/App needs overhaul/simplification before attempting to bring in CG4
    • CG4 similarly needs cleanup, especially re event handling
    • need to arrange CG4 and OpEngine to have a common high level OpticksEngine API
      • common aspects are: event handling/saving
  • bring over, cleanup, simplify G4DAEChroma gdc- (no need for ZMQ) with the customized step collecting Cerenkov and Scintillation processes
  • gun control interface, ImGui? particle palette, shooter mode
  • updated JUNO export, both DAE and GDML