Frank Nelles

I am a research associate and doctoral student at the Chair of Science and Technology for Peace and Security (PEASEC) in the Department of Computer Science at Technische Universität Darmstadt, primarily involved in the ATHENE PriVis, CROSSING, and emergenCity projects.

My research interests lie in the field of Human-Computer Interaction (HCI), with a particular focus on usable security and privacy.

I studied Computer Science (B.Sc. and M.Sc.) at Technische Universität Darmstadt, where I investigated Cross Reality (XR) applications in my master’s thesis. During my studies, I worked as an assistant researcher at the University Didactics Centre (HDA) in the field of electronic examinations and gained experience in Enterprise Architecture while working at Dentsu Aegis Network.

Selected Publications

CHI
A Qualitative Investigation of User Transitions and Frictions in Cross-Reality Applications

Julius von_Willich, Frank Nelles, Wen-Jie Tseng, and 3 more authors

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

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Research in Augmented Reality (AR) and Virtual Reality (VR) has mostly viewed them in isolation. Yet, when used together in practical settings, AR and VR each offer unique strengths, necessitating multiple transitions to harness their advantages. This paper investigates potential challenges in cross-reality (XR) transitions to inform future application design. We implemented an XR system featuring a 3D modeling task that requires users to switch between PC, AR, and VR. Using a think-aloud study (n=12) and thematic analysis, we revealed that frictions primarily arose when transitions conflicted with users’ Spatial Mental Model (SMM). Furthermore, we found five transition archetypes employed to enhance productivity once an SMM was established. Our findings uncover that transitions have to focus on establishing and upholding the SMM of users across realities, by communicating differences between them.
@inproceedings{vonwillich_qualitative_2025, dimensions = {true}, author = {von_Willich, Julius and Nelles, Frank and Tseng, Wen-Jie and Gugenheimer, Jan and G\"{u}nther, Sebastian and M\"{u}hlh\"{a}user, Max}, title = {A {{Qualitative Investigation}} of {{User Transitions}} and {{Frictions}} in {{Cross-Reality Applications}}}, booktitle = {Proceedings of the 2025 {{CHI Conference}} on {{Human Factors}} in {{Computing Systems}}}, year = {2025}, publisher = {Association for Computing Machinery}, url = {https://doi.org/10.1145/3706598.3713921}, doi = {10.1145/3706598.3713921} }
MuC
Demonstrating MagneTisch: Tangibles in Motion on an Interactive Surface

Sebastian Günther, Frank Nelles, Florian Horn, and 1 more author

In Proceedings of Mensch Und Computer 2022, 2022

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In this demonstration, we present MagneTisch, an interactive surface that can move, rotate, and modify 3D printed tangibles. A height-adjustable gripper arm grabs tangibles using magnets to move them to any location on the interactive table surface and also is able to rotate them as a whole or internal parts independently. In addition, the tangibles are externally tracked and a top-down projector can render digital content directly onto the surface and objects. Thereby, our demonstrator will showcase three applications: (1) a tangible virtual whiteboard, (2) a racing application, and (3) a tech demo highlighting all features.
@inproceedings{guenther_2022_demonstrating, dimensions = {true}, author = {G\"{u}nther, Sebastian and Nelles, Frank and Horn, Florian and M\"{u}hlh\"{a}user, Max}, title = {Demonstrating MagneTisch: Tangibles in Motion on an Interactive Surface}, year = {2022}, isbn = {9781450396905}, publisher = {Association for Computing Machinery}, address = {New York, NY, USA}, url = {https://doi.org/10.1145/3543758.3547520}, doi = {10.1145/3543758.3547520}, booktitle = {Proceedings of Mensch Und Computer 2022}, pages = {590–593}, numpages = {4}, keywords = {3D printing, interactive surface, magnets, tabletop, tangibles}, location = {Darmstadt, Germany}, series = {MuC '22} }