***** CALL FOR PARTICIPATION ***** Workshop "Transitional Interfaces in Mixed and Cross-Reality: A new frontier?" Hybrid Workshop at 2021 ACM Interactive Surfaces and Spaces Conference (ACM ISS 2021) Date: November 14, 2021 in Łódź, Poland Submission deadline: October 18, 2021, 23:59 AoE Website: https://idux-jetter.org/ti-iss2021/ ** ORGANIZERS ** Hans-Christian Jetter (University of Lübeck, Germany), Jan-Henrik Schröder (University of Lübeck, Germany), Jan Gugenheimer (Institut Polytechnique de Paris, Télécom Paris, France), Mark Billinghurst (University of South Australia, Australia and University of Auckland, New Zealand), Christoph Anthes (University of Applied Sciences Upper Austria, Hagenberg Campus, Austria), Mohamed Khamis (University of Glasgow, United Kingdom), Tiare Feuchtner (University of Konstanz, Germany) ** TOPIC OF THE WORKSHOP ** The rapid proliferation of powerful, yet affordable, off-the-shelf AR/VR head-mounted displays (HMDs) raises questions about how to better integrate such mixed reality technologies into our real-world computing ecosystems and into the real-world physical spaces they inhabit. We believe that in the future the concept of transitional interfaces (TIs), which was initially introduced by Billinghurst et al.'s "MagicBook" in 2001 [1], will provide a key lens through which mixed reality systems should be analysed, understood, and designed to achieve better integration. Billinghurst et al. already envisioned a system that enables a team of users (e.g., an architect and her clients) to move seamlessly between reality and immersive virtual reality while collaborating on the task at hand in the same physical space. We believe that similar to how cross-device interaction [2] has blended tabletop computers, digital whiteboards, and mobile devices with our familiar physical and social environment in meeting rooms [3] or even desk lamps [4], transitional interfaces could help us to seamlessly integrate systems from different locations along the RV-continuum [5] as usable, consistent, and coherent user interfaces in a shared physical space. Prior work has explored similar concepts: In their ISS 2020 workshop on cross-reality (XR), Simeone et al. [6] envisioned interfaces that enable "(i) a smooth transition between systems using different degrees of virtuality or (ii) collaboration between users using different systems with different degrees of virtuality". Riegler et al. [7] propose cross-virtuality (XV) as "a seamless integration and transition between conventional 2D visualization, augmented reality and virtual reality in order to provide users with optimal visual and algorithmic support with maximum cognitive and perceptual suitability, depending on their current tasks and needs". Our workshop is aimed at bringing together researchers who are working on TIs or related concepts such as XR or XV to create a common ground and mutual understanding for developing this space further. We believe that ACM ISS is an optimal venue for such work, since it brings together the extensive experience of researchers in the field of interactive surfaces and spaces including cross-device interaction and researchers from the AR/VR/XR/XV community. Focus topics of the workshop include but are not limited to: 1. Defining TIs: Identify differences and commonalities between transitional interfaces and related terms and terminologies (e.g., cross-reality, cross-virtuality, hybrid user interfaces). 2. Designing TIs: Compare and discuss designs of interaction and visualization techniques that support seamless transitions while maintaining situational and group awareness. 3. Evaluating TIs: Develop cognitive models or constructs for "seamlessness", "continuity", or other important qualities of TIs and discuss how to "measure" them in user studies and experiments. 4. Building TIs: Discuss and compare hard- and software that especially supports or hinders seamless transitions, e.g., video-based vs. optical see-through, different AR/VR engines, platforms for networked virtual environments. ** PROGRAM & SUBMISSIONS ** The full-day workshop will take place as a hybrid event as part of the 2021 ACM Interactive Surfaces and Spaces Conference (ACM ISS 2021) on November 14th in Łódź, Poland. We will ensure that anyone can effectively contribute to the workshop regardless of what the circumstances in November will be. ISS will offer virtual attendance opportunities. Please visit https://idux-jetter.org/ti-iss2021/ for more details and how to submit position papers. ** REFERENCES ** [1] M. Billinghurst, H. Kato, and I. Poupyrev. 2001. The MagicBook - moving seamlessly between reality and virtuality. IEEE Computer Graphics and Applications 21, 3 (2001), 6-8. https://doi.org/10.1109/38.920621 [2] Frederik Brudy, Christian Holz, Roman Rädle, Chi-Jui Wu, Steven Houben, Clemens Nylandsted Klokmose, and Nicolai Marquardt. 2019. Cross-Device Taxonomy: Survey, Opportunities and Challenges of Interactions Spanning Across Multiple Devices. In Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems. Association for Computing Machinery, New York, NY, USA, 1-28. https://doi.org/10.1145/3290605.3300792 [3] H.C. Jetter, H. Reiterer, and F. Geyer. 2014. Blended Interaction: Understanding Natural Human-Computer Interaction in Post-WIMP Interactive Spaces. Personal and Ubiquitous Computing 18, 5 (2014), 1139-1158. https://doi.org/10.1007/s00779-013-0725-4 [4] Roman Rädle, Hans-Christian Jetter, Nicolai Marquardt, Harald Reiterer, and Yvonne Rogers. 2014. HuddleLamp: Spatially-Aware Mobile Displays for Ad-Hoc Around-the-Table Collaboration. In Proceedings of the Ninth ACM International Conference on Interactive Tabletops and Surfaces (Dresden, Germany) (ITS '14). Association for Computing Machinery, New York, NY, USA, 45-54. https://doi.org/10.1145/2669485.2669500 [5] P. Milgram and F. Kishino. 1994. A Taxonomy of Mixed Reality Visual Displays. IEICE Transactions on Information and Systems E77-D, 12 (1994),1321-1329. [6] Adalberto L. Simeone, Mohamed Khamis, Augusto Esteves, Florian Daiber, Matjaž Kljun, Klen Čopič Pucihar, Poika Isokoski, and Jan Gugenheimer. 2020. International Workshop on Cross-Reality (XR) Interaction. In Companion Proceedings of the 2020 Conference on Interactive Surfaces and Spaces (Virtual Event, Portugal) (ISS '20). Association for Computing Machinery, New York, NY, USA, 111-114. https://doi.org/10.1145/3380867.3424551 [7] A. Riegler, C. Anthes, H.C. Jetter, C. Heinzl, C. Holzmann, H. Jodlbauer, M. Brunner, S. Auer, J. Friedl, and B. Fröhler. 2020. Cross-Virtuality Visualization, Interaction and Collaboration. In International Workshop on Cross-Reality (XR) Interaction @ ACM ISS 2020. http://ceur-ws.org/Vol-2779/paper1.pdf