Tangible User Interface (TUI) represents a huge potential for Virtual Reality (VR) because tangibles can naturally provide rich haptic cues which are often missing in VR experiences that make use of standard controllers. We are particularly interested in implementing TUIs for smartphone-based VR, given the lower usage barrier and easy deployment. In order to keep the overall system simple and accessible, we have explored object detection through visual markers, using the smartphone’s camera. In order to help VR experience designers, in this work we present a design space for marker-based TUI for VR. We have mapped this design space by developing several marker-based tangible interaction prototypes and through a formative study with professionals with different backgrounds. We then instantiated the design space in a Tangible VR Book which we evaluate with remote user studies inspired by the vignette methodology.

In this work we present three prototypes of the tangible VR Book: a visual marker-based solution to tangible interaction for smartphonebased Virtual Reality (VR). Smartphone-based VR represents a low barrier to entry in VR experiences given that many people nowadays own a smartphone device and that VR headsets for these devices are affordable and quick to set up when compared to desktopbased VR. Tangible interaction in smartphone-based VR has not been much explored, in our opinion, despite the fact that it can result in easy to use and engaging experiences. In this work, we explore a marker-based solution to object tracking that allows tangibles to be created in an easy and cheap way, maintaining the overall system accessible. We describe a design space for visual marker-based tangible interaction and three prototypes of a tangible VR Book that explore different aspects of the design space. We also present user feedback on their expectations regarding the interaction with the VR Book. CCS CONCEPTS• Human-centered computing → Virtual reality; Smartphones; Ubiquitous and mobile computing design and evaluation methods.