Users specify which local transform to apply to global coordinates (which frame is the global one, really universe ?) by means of DE (detector element) names starting /dd/Structure/...
In order to make sense of any such coordinates (eg to display ntuple/histogram content within the 3D representation) need to have access to the G4AffineTransforms for all DE. Currently the IDMAP machinery only caches transforms for cathode volumes with PmtId attached.
TODO:
All DE are traversed by:
[blyth@ntugrid5 ~]$ which de.sh
~/env/bin/de.sh