Debugging Cyber-Physical Systems: The Impact of Anchoring Strategies and Degree of Virtuality of Debugging...

Debugging Cyber-Physical Systems like Digital Twins requires developers to mentally bridge the gap between two dimensional source code and three-dimensional physical behavior. While Augmented Reality (AR) offers potential for immersive debugging by spatially anchoring information, Virtual Reality (VR) might serve as a suitable substitute when physical entities are not (yet) available or are inaccessible. In this paper, we investigate the impact of additional in-situ visualizations, placed next to the physical entity, versus additional ex-situ visualizations, placed next to the IDE. Furthermore, we evaluate the degree of virtuality by comparing these in-situ visualizations across AR and VR environments to assess VR's suitability as a substitute. We conducted a within-subject laboratory study (N = 36) using a distributed robotic scenario to evaluate debugging performance and experience across three conditions: Ex-Situ AR, In-Situ AR, and In-Situ VR. Results indicate that in-situ visualizations significantly enhance usability and user experience compared to ex-situ visualizations, even when objective performance metrics were comparable. Qualitative analysis reveals a trade-off between the spatial awareness of AR and the abstracted focus of VR, as well as a preference for the clear spatial assignment provided by in-situ panels. Our findings suggest that while in-situ visualizations do not necessarily speed up the resolution of bugs, they provide a more intuitive and satisfying workflow for identifying and fixing them.