Mechatronic systems are a synergy of mechanical and software components. System behaviour is dependent on the software interaction with non-software components and therefore both aspects need to be considered in system design. 3D UML Mechatronic Diagrams use a 3D model of the Unified Modelling Language (UML) to integrate a software model view with a mechanical view to aid in the understanding of the system as a whole. We present the results of implementing 3D UML Mechatronic Diagrams for real-time debugging of robot behaviour through augmented reality.