Accessing GDML geometry

Hello experts,

I have a geometry in gdml which was imported into my detectorconstruction. I was able to access the logical volumes including the gdml logical volumes via:

G4LogicalVolumeStore* lvs = G4LogicalVolumeStore::GetInstance();
std::vector<G4LogicalVolume*>::const_iterator lvciter;
for( lvciter = lvs->begin(); lvciter != lvs->end(); lvciter++ )
if ((*lvciter)->GetName() == “straw_tube_copper”)


I made straw_tube_copper (gdml volume) the daughter of a volume (Tube) defined in the DetectorConstruction. Surprisingly, the straw_tube_copper volume sits outside the Tube despite their position are both (0,0,0).

Can someone please tell me why the straw_tube_copper is not sitting inside the tube?

Thank you
Aliyu Bala