Get local position on the mother volume

Hi experts!
I have a geometry with this schematic configuration:

| ---------------------------- |
| World |
| | ------------------------- | |
| |. Mother | |
| | \ ---------------------- \ | |
| | . Daughter \ | |
| | \ ---------------------- \ | |
| | ------------------------- | |
| ---------------------------- |

I want to get the position in the mother volume, but using these cmds I obtain the transformation to local position in the Daughter volume:

G4ThreeVector worldPosition = prePoint->GetPosition();
G4ThreeVector localPosition = touchable->GetHistory()->GetTopTransform().TransformPoint(worldPosition);

What could I do?
Thxs in advance.
Dayron.