Unexpected result of GetTranslation(G4int depth) function

Geometry, Fields and Transportation
1

I’m trying to get the global position of a physical volume as well as its mother’s with GetTranslation(G4int depth) function. However, the outputed global position of its mother is inversed, I’m really confused. Here is an example, the geometry construction is like this:

G4bool CheckOverlaps = true;
auto solidWorld = new G4Box("solidLWorld", 10.*m, 10.*m, 10.*m);
auto logicWorld = new G4LogicalVolume(solidWorld, MatConstructor->Get("LAr"), "logicWorld");
auto physWorld = new G4PVPlacement(0, G4ThreeVector(), logicWorld, "World", 0, false, 0, CheckOverlaps);

auto solidLAr = new G4Box("solidLAr", 3.*m, 3.*m, 3.*m);
auto logicLAr = new G4LogicalVolume(solidLAr, MatConstructor->Get("LAr"), "logicLAr");
auto physLAr = new G4PVPlacement(0, G4ThreeVector(-1.*m, 0., 0.), logicLAr, "LAr", logicWorld, false, 0, CheckOverlaps);

G4double fUnitHeight = 100.*mm;
G4double fUnitRadius = 65.*mm;
auto solidBeGe = new G4Tubs("bege", 0, fUnitRadius, fUnitHeight/2., 0, twopi);
auto logicBeGe = new G4LogicalVolume(solidBeGe, MatConstructor->Get("EnGe"), "logicGe");
auto physBEGe = new G4PVPlacement(0, G4ThreeVector(-10.*cm, -20.*cm, -30.*cm), logicBeGe, "BEGe", logicLAr, false, 0, CheckOverlaps);
return physWorld;

And in stepping action like this:

auto fPhyName = fPhysicalVolume->GetName();
if(fPhyName == "BEGe"){
G4cout<< "0: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetVolume(0)->GetName()<<G4endl;
G4cout<< "0: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetTranslation(0) << G4endl;
G4cout<< "1: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetVolume(1)->GetName()<<G4endl;
G4cout<< "1: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetTranslation(1) << G4endl;
G4cout<< "2: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetVolume(2)->GetName()<<G4endl;
G4cout<< "2: "<<step->GetPreStepPoint()->GetTouchableHandle()->GetTranslation(2) << G4endl;
}

According to the result: BEGe (-1100, -200, -300), this is the right global position. However for LAr (1000,0,0). The global position of it should be (-1000, 0, 0). Does anyone know why it is inversed? Thank you very much!
_Geant4 Version:_11.1.2
Operating System: ubuntu 22.04
_Compiler/Version:_gcc version 11.4.0 (Ubuntu 11.4.0-2ubuntu1~20.04)
_CMake Version:_cmake version 3.16.3

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