[12gevmoller_sim] [JeffersonLab/remoll] 02cf52: Parallel world support.

[GitHub]

  Branch: refs/heads/pion
  Home:   https://github.com/JeffersonLab/remoll
  Commit: 02cf527c23d45547748b673ba75e272fc68b6cb1
      https://github.com/JeffersonLab/remoll/commit/02cf527c23d45547748b673ba75e272fc68b6cb1
  Author: Wouter Deconinck <wdconinc at gmail.com>
  Date:   2017-04-17 (Mon, 17 Apr 2017)

  Changed paths:
    A geometry_sculpt/parallelWorld.gdml
    A include/remollParallelWorldConstruction.hh
    A src/remollParallelWorldConstruction.cc

  Log Message:
  -----------
  Parallel world support.

What are parallel worlds (good for)? In geant4 they are non-material
worlds that can be used for sensitive detectors etc. The volumes in
the parallel world can overlap arbitrarily with material volumes in
the real world (but they can't overlap with themselves, just like any
geometry). We can use them for virtual detectors, if that makes sense,
or we can use them just for visualization aspects. I've taken the
second route here by adding a cone to represent the ee scattering
sheet in the pion detector region. One could expand this to other
backgrounds etc. This is plainly a visualization solution, no physics
is changed by this.

Caveat: there's no messenger to set the parallel world gdml, so for
now only parallelWorld.gdml is supported.