AFatrasG4Tool Node1 AFatrasG4Tool - m_doG4Transport - m_ActsFatrasG4Tool - m_pixelHitsKey - m_sctHitsKey + AFatrasG4Tool() # initializeFastSim() # BeginOfAthenaEvent() # EndOfAthenaEvent() # makeFastSimModel() Node2 FastSimulationBase # m_regionName # m_noRegions + FastSimulationBase() + initializeFastSim() + BeginOfAthenaEvent() + EndOfAthenaEvent() # getRegion() Node2->Node1 Node3 extends< AthAlgTool, IFastSimulation >     Node3->Node2