Florian Müller

I am an Assistant Professor for Mobile Human-Computer Interaction at TU Darmstadt where I lead the Urban Interaction Lab. My research follows the vision of seamless mobile interaction in and with the physical world, where digital information, AI agents, and physical environments merge into a unified eXtended Reality. Towards this vision, I explore novel interaction techniques for mobile XR and collaboration with AI systems. My approach is informed by a deep understanding of body-centric, tangible and haptic interfaces, as well as strong technical expertise, aiming to make the interaction more efficient and accurate but also more enjoyable and fun.

latest publications

2025

The Bitter Taste of Confidence: Exploring Audio-Visual Taste Modulation in Immersive Reality

Pooria Ghavamian, Jan Henri Beyer, Sophie Orth, Mia Johanna Nona Zech, Florian Müller, and Andrii Matviienko

In Proceedings of the 2025 ACM International Conference on Interactive Media Experiences, May 2025

PDF ACM

Extended Reality (XR) technologies present innovative ways to augment sensory experiences, including taste perception. In this study, we investigated how augmented reality (AR) visual filters and synchronized audio cues affect gustation through a controlled experiment with 18 participants. Our findings revealed unexpected crossmodal interactions: while pink visual filter typically associated with sweetness reduced perceived bitterness in isolation, it paradoxically enhanced bitterness perception when combined with sweet-associated audio cue. Furthermore, we observed an inverse correlation between participant confidence levels and their perception of taste intensities across multiple dimensions, highlighting confidence as an overlooked factor in sensory experience design. These findings inform the design of nuanced multisensory experiences in immersive media, where subtle crossmodal interactions significantly influence user perception.
Social MediARverse: Investigating Users’ Social Media Content Sharing and Consuming Intentions with Location-Based AR

Linda Hirsch, Florian Mueller, Mari Kruse, Andreas Butz, and Robin Welsch

Virtual Reality, Jul 2025

PDF Springer arxiv

Augmented Reality (AR) is evolving to become the next frontier in social media, merging physical and virtual reality into a living metaverse, a Social MediARverse. With this transition, we must understand how different contexts—public, semi-public, and private—affect user engagement with AR content. We address this gap in current research by conducting an online survey with 110 participants, showcasing 36 AR videos, and polling them about the content’s fit and appropriateness. Specifically, we manipulated these three spaces, two forms of dynamism (dynamic vs. static), and two dimensionalities (2D vs. 3D). Our findings reveal that dynamic AR content is generally more favorably received than static content. Additionally, users find sharing and engaging with AR content in private settings more comfortable than in others. By this, the study offers valuable insights for designing and implementing future Social MediARverses and guides industry and academia on content visualization and contextual considerations.
Don’t They Really Hear Us? A Design Space for Private Conversations in Social Virtual Reality

Josephus Jasper Limbago, Robin Welsch, Florian Müller, and Mario Di Francesco

IEEE Transactions on Visualization and Computer Graphics, Jul 2025

PDF IEEE

Seamless transition between public dialogue and private talks is essential in everyday conversations. Social Virtual Reality (VR) has revolutionized interpersonal communication by creating a sense of closeness over distance through virtual avatars. However, existing social VR platforms are not successful in providing safety and supporting private conversations, thereby hindering self-disclosure and limiting the potential for meaningful experiences. We approach this problem by exploring the factors affecting private conversations in social VR applications, including the usability of different interaction methods and the awareness with respect to the virtual world. We conduct both expert interviews and a controlled experiment with a social VR prototype we realized. We then leverage the outcomes of the two studies to establish a design space that considers diverse dimensions (including privacy levels, social awareness, and modalities), laying the groundwork for more intuitive and meaningful experiences of private conversation in social VR.
AR You on Track? Investigating Effects of Augmented Reality Anchoring on Dual-Task Performance While Walking

Julian Rasch, Matthias Wilhalm, Florian Müller, and Francesco Chiossi

In Proceedings of the 2025 CHI Conference on Human Factors in Computing Systems - CHI ’25, Jul 2025

PDF ACM arxiv

With the increasing spread of AR head-mounted displays suitable for everyday use, interaction with information becomes ubiquitous, even while walking. However, this requires constant shifts of our attention between walking and interacting with virtual information to fulfill both tasks adequately. Accordingly, we as a community need a thorough understanding of the mutual influences of walking and interacting with digital information to design safe yet effective interactions. Thus, we systematically investigate the effects of different AR anchors (hand, head, torso) and task difficulties on user experience and performance. We engage participants (n=26) in a dual-task paradigm involving a visual working memory task while walking. We assess the impact of dual-tasking on both virtual and walking performance, and subjective evaluations of mental and physical load. Our results show that head-anchored AR content least affected walking while allowing for fast and accurate virtual task interaction, while hand-anchored content increased reaction times and workload.
CreepyCoCreator? Investigating AI Representation Modes for 3D Object Co-Creation in Virtual Reality

Julian Rasch, Julia Töws, Teresa Hirzle, Florian Müller, and Martin Schmitz

In Proceedings of the 2025 CHI Conference on Human Factors in Computing Systems - CHI ’25, Jul 2025

PDF ACM arxiv

Generative AI in Virtual Reality offers the potential for collaborative object-building, yet challenges remain in aligning AI contributions with user expectations. In particular, users often struggle to understand and collaborate with AI when its actions are not transparently represented. This paper thus explores the co-creative object-building process through a Wizard-of-Oz study, focusing on how AI can effectively convey its intent to users during object customization in Virtual Reality. Inspired by human-to-human collaboration, we focus on three representation modes: the presence of an embodied avatar, whether the AI’s contributions are visualized immediately or incrementally, and whether the areas modified are highlighted in advance. The findings provide insights into how these factors affect user perception and interaction with object-generating AI tools in Virtual Reality as well as satisfaction and ownership of the created objects. The results offer design implications for co-creative world-building systems, aiming to foster more effective and satisfying collaborations between humans and AI in Virtual Reality.
A Vision for AI-Driven Adaptation of Dynamic AR Content to Users and Environments

Julian Rasch, Florian Müller, and Francesco Chiossi

Apr 2025

PDF arxiv

Augmented Reality (AR) is transforming the way we interact with virtual information in the physical world. By overlaying digital content in real-world environments, AR enables new forms of immersive and engaging experiences. However, existing AR systems often struggle to effectively manage the many interactive possibilities that AR presents. This vision paper speculates on AI-driven approaches for adaptive AR content placement, dynamically adjusting to user movement and environmental changes. By leveraging machine learning methods, such a system would intelligently manage content distribution between AR projections integrated into the external environment and fixed static content, enabling seamless UI layout and potentially reducing users’ cognitive load. By exploring the possibilities of AI-driven dynamic AR content placement, we aim to envision new opportunities for innovation and improvement in various industries, from urban navigation and workplace productivity to immersive learning and beyond. This paper outlines a vision for the development of more intuitive, engaging, and effective AI-powered AR experiences.
Through the Expert’s Eyes: Exploring Asynchronous Expert Perspectives and Gaze Visualizations in XR

Clara Sayffaerth, Annika Köhler, Julian Rasch, Albrecht Schmidt, and Florian Müller

Aug 2025

PDF arxiv

Transferring knowledge across generations is fundamental to human civilization, yet the challenge of passing on complex practical skills persists. Methods without a physically present instructor, such as videos, often fail to explain complex manual tasks, where spatial and social factors are critical. Technologies such as eXtended Reality and Artificial Intelligence hold the potential to retain expert knowledge and facilitate the creation of tailored, contextualized, and asynchronous explanations regardless of time and place. In contrast to videos, the learner’s perspective can be different from the recorded perspective in XR. This paper investigates the impact of asynchronous first- and third-person perspectives and gaze visualizations on efficiency, feeling of embodiment, and connectedness during manual tasks. The empirical results of our study (N=36) show that the first-person perspective is better in quantitative measures and preferred by users. We identify best practices for presenting preserved knowledge and provide guidelines for designing future systems.
From Pegs to Pixels: A Comparative Analysis of the Nine Hole Peg Test and a Digital Copy Drawing Test for Fine Motor Control Assessment

Dominik Schön, Thomas Kosch, Martin Schmitz, Sebastian Günther, Max Mühlhäuser, and Florian Müller

Proc. ACM Hum.-Comput. Interact., Sep 2025

PDF ACM data

User interaction with digital systems requires Fine Motor Control (FMC), especially if the interfaces are complex or require high fidelity and fine-grained interactions. Despite its importance, Fine Motor Control is often overlooked in interactive system design, partly because of its complex assessment. Measuring changes in fine motor abilities due to prolonged use or fatigue currently requires repeated manual testing. This paper analyzes the concept of using the digital mobile devices’ input behavior to assess the user’s Fine Motor Control. For this, we show that Fine Motor Control can be assessed for touch and stylus-based interaction with a digital mobile system. We conducted a user study, where participants performed a Nine Hole Peg Test and a predefined Copy Drawing Test before and after exercises that affect fine motor skills. Based on this data, we investigated how metrics such as pressure, velocity, and entropy for touch and stylus input can be used to predict Fine Motor Control.
Assessing Visualization and Interaction Techniques to Support Comparison Tasks in Virtual Reality

Henrike Weingärtner, Julian Rasch, Nils Rothamel, and Florian Müller

In Proceedings of the Extended Abstracts of the CHI Conference on Human Factors in Computing Systems, Apr 2025

PDF ACM

Desktop screens are effective for supporting comparison tasks, but as the scale increases to room-sized or larger structures, context is lost. Users are forced to focus on isolated details through panning, zooming, and scrolling, making it difficult to maintain an overview while exploring finer details. Virtual Reality (VR) potentially offers a solution to this problem by immersing users in 3D spaces and enabling more intuitive comparisons. While related work has proposed many solutions for visualizing and interacting for comparison tasks in desktop environments, knowledge regarding the efficacy of supporting such tasks in VR environments is still lacking. We investigated varying visualization and interaction techniques in a controlled experiment with 24 participants. Our findings provide valuable insights for designing VR systems that improve usability, reduce workload, and enhance performance in comparison tasks.
Investigating the Effects of Haptic Illusions in Collaborative Virtual Reality

Yannick Weiss, Julian Rasch, Jonas Fischer, and Florian Müller

IEEE Transactions on Visualization and Computer Graphics, Apr 2025

PDF IEEE

Our sense of touch plays a crucial role in physical collaboration, yet rendering realistic haptic feedback in collaborative extended reality (XR) remains a challenge. Co-located XR systems predominantly rely on prefabricated passive props that provide high-fidelity interaction but offer limited adaptability. Haptic Illusions (HIs), which leverage multisensory integration, have proven effective in expanding haptic experiences in single-user contexts. However, their role in XR collaboration has not been explored. To examine the applicability of HIs in multi-user scenarios, we conducted an experimental user study (N=30) investigating their effect on a collaborative object handover task in virtual reality. We manipulated visual shape and size individually and analyzed their impact on users’ performance, experience, and behavior. Results show that while participants adapted to the illusions by shifting sensory reliance and employing specific sensorimotor strategies, visuo-haptic mismatches reduced both performance and experience. Moreover, mismatched visualizations in asymmetric user roles negatively impacted performance. Drawing from these findings, we provide practical guidelines for incorporating HIs into collaborative XR, marking a first step toward richer haptic interactions in shared virtual spaces.
One Does Not Simply Meme Alone: Evaluating Co-Creativity Between LLMs and Humans in the Generation of Humor

Zhikun Wu, Thomas Weber, and Florian Müller

In Proceedings of the 30th International Conference on Intelligent User Interfaces, Mar 2025

PDF ACM arxiv

Collaboration has been shown to enhance creativity, leading to more innovative and effective outcomes. While previous research has explored the abilities of Large Language Models (LLMs) to serve as co-creative partners in tasks like writing poetry or creating narratives, the collaborative potential of LLMs in humor-rich and culturally nuanced domains remains an open question. To address this gap, we conducted a user study to explore the potential of LLMs in co-creating memes—a humor-driven and culturally specific form of creative expression. We conducted a user study with three groups of 50 participants each: a human-only group creating memes without AI assistance, a human-AI collaboration group interacting with a state-of-the-art LLM model, and an AI-only group where the LLM autonomously generated memes. We assessed the quality of the generated memes through crowdsourcing, with each meme rated on creativity, humor, and shareability. Our results showed that LLM assistance increased the number of ideas generated and reduced the effort participants felt. However, it did not improve the quality of the memes when humans were collaborated with LLM. Interestingly, memes created entirely by AI performed better than both human-only and human-AI collaborative memes in all areas on average. However, when looking at the top-performing memes, human-created ones were better in humor, while human-AI collaborations stood out in creativity and shareability. These findings highlight the complexities of human-AI collaboration in creative tasks. While AI can boost productivity and create content that appeals to a broad audience, human creativity remains crucial for content that connects on a deeper level.
Pull Requests From The Classroom: Co-Developing Curriculum And Code

Dennis Zyska, Ilia Kuznetsov, Florian Müller, and Iryna Gurevych

In Proceedings of Mensch Und Computer 2025 - MuC ’25, Aug 2025

PDF ACM arxiv

Educational technologies often misalign with instructors’ pedagogical goals, forcing adaptations that compromise teaching efficacy. In this paper, we present a case study on the co-development of curriculum and technology in the context of a university course on scientific writing. Specifically, we examine how a custom-built peer feedback system was iteratively developed alongside the course to support annotation, feedback exchange, and revision. Results show that while co-development fostered stronger alignment between software features and course goals, it also exposed usability limitations and infrastructure-related frustrations, emphasizing the need for closer coordination between teaching and technical teams.

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