WIP: G4VecGeomConverter : initialise MaterialPtr & MaterialCutsPtr to indices.
Draft revision to initialize VecGeom LogicalVolume's material related data members:
MaterialPtr = g4material.instanceID MaterialCutPtr = g4materialCutsCouple.index
Draft revision to initialize VecGeom LogicalVolume's material related data members:
MaterialPtr = g4material.instanceID MaterialCutPtr = g4materialCutsCouple.index