At the end of April 2025, I had the opportunity to travel to Yokohama, Japan, to attend ACM CHI 2025, the world’s largest conference in the field of Human-Computer Interaction. Together with Julius von Willich, we were able to present our paper “A Qualitative Investigation of User Transitions and Frictions in Cross-Reality Applications”. Our work explores the challenges users face when transitioning between PC, AR, and VR in Cross-Reality (CR) systems. Using a 3D modelling task in a talk-aloud study, we found that such transitions often lead to friction when they conflict with users’ spatial mental models (SMMs). A key insight of the paper is that clearly communicating differences between realities is essential to help users maintain their mental models and work effectively across modalities.

The conference not only provided a venue to present our research, but also an impressive range of current topics, trends and discussions in the field of human-computer interaction, mostly focusing on AI and XR research. I found it particularly enriching to gain a broader perspective on interdisciplinary fields—especially those connected to my current research focus on Usable Security and Privacy.

Frank Nelles standing in front of the CHI 2025 Logo
© Frank Nelles

Associated emergenCITY WiMi Frank Nelles presented his paper at the CHI 2025

Outside the conference, there was also time to experience Japan’s rich culture. I was deeply impressed by the country’s aesthetic beauty, delicious food, and historical significance—most notably during a visit to Hiroshima. At the same time, I noticed unique everyday quirks, such as the omnipresence of 24/7 convenience stores, vending machines on nearly every corner, and a remarkable abundance of plastic packaging. Attending CHI 2025 expanded my academic horizon, inspired numerous new ideas, and significantly extended my reading list. I am especially grateful to PEASEC, the Telecooperation group, and emergenCITY for their financial and academic support, which made this experience possible at such an early stage in my research career.

About the Author

Frank Nelles is a research associate and doctoral student with the group Science and Technology for Peace and Security (PEASEC) at TU Darmstadt and associated with emergenCITY. He works in the area of Usable Privacy & Security with a focus on bystander and group privacy. He completed his Master’s degree in Computer Science at TU Darmstadt in 2024. The presented paper is based on his Master’s thesis conducted with the Telecooperation Group.

Paper

Julius von Willich, Frank Nelles, Wen-Jie Tseng, Jan Gugenheimer, Sebastian Günther, and Max Mühlhäuser 2025 A Qualitative Investigation of User Transitions and Frictions in Cross-Reality Applications In Proceedings of the 2025 CHI Conference on Human Factors in Computing Systems (CHI ‘25) Association for Computing Machinery, New York, NY, USA, Article 808, 1–18