A minimal failing example (based on example B1) can be found here: https://github.com/Geant4/geant4/compare/master...loximann:parallel_world_bug?expand=1 Setup: * Removed Shape1 from physical world. * Added a parallel world with a volume identical to Shape2 The issue: No parallel world processes are observed: G4WT13 > ********************************************************************************************************* G4WT13 > * G4Track Information: Particle = geantino, Track ID = 1, Parent ID = 0 G4WT13 > ********************************************************************************************************* G4WT13 > G4WT13 > Step# X Y Z KineE dEStep StepLeng TrakLeng Volume Process G4WT13 > 0 0 fm 0 fm -15 cm 6 MeV 0 eV 0 fm 0 fm Envelope initStep G4WT13 > 1 0 fm 0 fm 4 cm 6 MeV 0 eV 19 cm 19 cm Envelope CoupledTransportation G4WT13 > 2 0 fm 0 fm 10 cm 6 MeV 0 eV 6 cm 25 cm Shape2 CoupledTransportation G4WT13 > 3 0 fm 0 fm 15 cm 6 MeV 0 eV 5 cm 30 cm Envelope CoupledTransportation G4WT13 > 4 0 fm 0 fm 18 cm 6 MeV 0 eV 3 cm 33 cm World OutOfWorld However, if a 1 nm displacement is added to the parallel world volume, "MyParallelWorld" processes are observed. G4WT2 > ********************************************************************************************************* G4WT2 > * G4Track Information: Particle = geantino, Track ID = 1, Parent ID = 0 G4WT2 > ********************************************************************************************************* G4WT2 > G4WT2 > Step# X Y Z KineE dEStep StepLeng TrakLeng Volume Process G4WT2 > 0 0 fm 0 fm -15 cm 6 MeV 0 eV 0 fm 0 fm Envelope initStep G4WT2 > 1 0 fm 0 fm 4 cm 6 MeV 0 eV 19 cm 19 cm Envelope CoupledTransportation G4WT2 > 2 0 fm 0 fm 4 cm 6 MeV 0 eV 10 Ang 19 cm Shape2 MyParallelWorld G4WT2 > 3 0 fm 0 fm 10 cm 6 MeV 0 eV 6 cm 25 cm Shape2 CoupledTransportation G4WT2 > 4 0 fm 0 fm 10 cm 6 MeV 0 eV 10 Ang 25 cm Envelope MyParallelWorld G4WT2 > 5 0 fm 0 fm 15 cm 6 MeV 0 eV 5 cm 30 cm Envelope CoupledTransportation G4WT2 > 6 0 fm 0 fm 18 cm 6 MeV 0 eV 3 cm 33 cm World OutOfWorld
If volumes in the "real" world and a parallel world share the volume boundary, the G4CoupledTransportation process is shown as the process that limits the step. This does NOT mean the volume in a parallel world is ignored. The following step is seen by both volumes in real world and the parallel world. Thus what you see is a correct behavior and nothing is misbehaving. If you would like to confirm, assign a sensitive detector to the volume in the parallel world and add G4cout to see.
I added sensitive detectors and indeed you are right, I am sorry for wasting your time :-/ Has anything been fixed in recent versions? I recall that months ago I was getting wrong results with a more complicated setup involving replicas both in the physical world and the parallel world.
Hi Sergio, if you experience any problem you should report them giving clear evidence and way to reproduce them (and possibly as a ticket in this system rather than through posts in the Forum). Generic statements don't help either. We are not aware of misbehaviours in this area; no issues have been reported to us.
Apparently there was an issue like the one I meant to report, but it has already been fixed: https://geant4-forum.web.cern.ch/t/stepstatus-depending-on-scoring-mesh/6121/2
