G4/Op Integration Overview

Objectives

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

Approach

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:

/usr/local/env/geant4/geometry/export/DayaBay_VGDX_20140414-1300/

DONE

• 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

DEBUGGING

• nopstep visualization

TODO

• 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