Cross-reality is an emerging research area concerned with systems operating across different points on the reality-virtuality continuum. These systems are often complex, involving multiple realities and users, and thus there is a need for an overarching design framework, which, despite growing interest has yet to be developed. This paper addresses this need by presenting eleven design patterns for cross-reality applications across the following four categories: fundamental, origin, display, and interaction patterns. To develop these design patterns we analysed a sample of 60 papers, with the goal of identifying recurring solutions. These patterns were then described in form of intent, solution, and application examples, accompanied by a diagram and archetypal example. This paper provides designers with a comprehensive set of patterns that they can use and draw inspiration from when creating cross-reality systems.

The aim of this study is to develop an understanding of how virtual objects can be transitioned between 3D Augmented Reality and 2D standard monitor display spaces. The increased availability of Augmented Reality devices, in combination with the prevalence of conventional desktop setups with mouse and keyboard input, gives rise to future hybrid setups in which users may need to transition virtual objects between display spaces. We developed three virtual object transition techniques: Mouse-based, Hand-based, and a Modality Switch (where users can only use the input methods in their respective display spaces). The three techniques were evaluated in a user study (N=24) alongside a fourth condition in which participants could freely switch between Hand and Mouse-based techniques. Participants were tasked with transitioning virtual bricks from 3D space onto the screen, then using the mouse to make fine adjustments, such as choosing the colour of the brick and placing decorations, to then transition them back into 3D space to build with. The Modality Switch technique was not preferred due to higher mental demand. Participants preferred the mouse-based technique, which allowed them to transition the virtual bricks faster.

Cross-Reality Transitional Interfaces support tasks that require interactions at different levels of virtuality. However, there is little knowledge on how such capabilities can be scaled on vertical and life-sized surfaces, by offering haptic feedback, transitioning the surface between physical and virtual environments, and moving the surface at room-scale. The aim of our study is to generate an empirical understanding of which combinations of mixed reality and a user-controlled movable robotic surface (resulting in four virtuality levels) are better suited to execute five tasks, which differed in terms of haptic feedback. During our user study (N=24), physical environment-physical surface was used most due to its familiarity and haptic feedback, while the virtual environment mode was experienced as more relaxing and fun, and the virtual surface mode as more convenient and safer.

In the domain of Human-Computer Interaction, focus groups represent a widely utilised yet resource-intensive methodology, often demanding the expertise of skilled moderators and meticulous preparatory efforts. This study introduces the “Focus Agent,” a Large Language Model (LLM) powered framework that simulates both the focus group (for data collection) and acts as a moderator in a focus group setting with human participants. To assess the data quality derived from the Focus Agent, we ran five focus group sessions with a total of 23 human participants as well as deploying the Focus Agent to simulate these discussions with AI participants. Quantitative analysis indicates that Focus Agent can generate opinions similar to those of human participants. Furthermore, the research exposes some improvements associated with LLMs acting as moderators in focus group discussions that include human participants.

Locating out-of-view vehicles can help pedestrians to avoid critical traffic encounters. Some previous approaches focused solely on visualising out-of-view objects, neglecting their localisation and limitations. Other methods rely on continuous camera-based localisation, raising privacy concerns. Hence, we propose the ARcoustic system, which utilises a microphone array for nearby moving vehicle localisation and visualises nearby out-of-view vehicles to support pedestrians. First, we present the implementation of our sonic-based localisation and discuss the current technical limitations. Next, we present a user study (n = 18) in which we compared two state-of-the-art visualisation techniques (Radar3D, CompassbAR) to a baseline without any visualisation. Results show that both techniques present too much information, resulting in below-average user experience and longer response times. Therefore, we introduce a novel visualisation technique that aligns with the technical localisation limitations and meets pedestrians’ preferences for effective visualisation, as demonstrated in the second user study (n = 16). Lastly, we conduct a small field study (n = 8) testing our ARcoustic system under realistic conditions. Our work shows that out-of-view object visualisations must align with the underlying localisation technology and fit the concrete application scenario.

In this work, we describe our experience developing and evaluating the Cross-Reality Study Tool (CReST), which allows researchers to conduct and observe Virtual Reality (VR) user studies from an Augmented Reality perspective. So far, most research on conducting VR user studies has centred around tools for asynchronous setup, data collection and analysis, or (immersive) replays. Conversely, CReST is centred around supporting the researcher synchronously. We replicated three VR studies as example cases, applied CReST to them, and conducted an interview with one author of each case. We then performed a case study, and recruited 17 participants to take part in a user study where the researchers used CReST to observe participant interaction with virtual drawer and closet artefacts. We make CReST available for other researchers, as a tool to enable direct observation of participants in VR, and perform rapid, qualitative evaluations.

Shared Augmented Environments (AEs) introduce both opportunities and challenges in terms shared content and privacy. We present three abstraction techniques to balance privacy and context in collaborative Augmented Reality (AR) applications. We developed three abstraction techniques, polygon count reduction (PCR), blurring, and blurred PCR (BPCR). We conducted a study aimed to evaluate the effects of these techniques on object recognition in AR. Results indicate that altering shape and material significantly impacts the certainty and ability of object recognition, with variations observed across different object types. The implications of this research extend to the design and implementation of privacy-aware collaborative AR applications, emphasising the need to strike a balance between providing context and respecting user privacy.

In this paper we present Immersive Speculative Enactments (ISEs), a novel concept that extends conventional Speculative Enactments to Virtual Reality. Through ISEs, participants are immersed in a speculative world depicted by the designers and can engage with it in its truest envisioned form. We explore this concept via four scenarios with increasing technological uncertainty: a glimpse in the daily life of the parent of a newborn baby; a Mixed Reality experience supporting hybrid classrooms; two wearable devices that present a pet’s emotional state and needs; and an enactment on the effect of communication delay across interplanetary distances. We discuss the concept of ISEs and contrast them to other forms of speculation, provide guidelines on how to design them, as well as reflecting on the challenges, limitations, and potential associated with the role of ISEs in the HCI discourse.

Cross-Reality (CR) involves interaction between different modalities and levels of immersion such as Virtual and Augmented Reality, as we explore in this paper. Whereas previous work assumed similarity between their respective Virtual and Augmented Environment (VE and AE), we explore the case in which VE and AE are distinct. This gives rise to novel and critical problems, such as how to visualise and interact with the other environment. In this context we investigate the fundamental interaction of transitioning an object across environments, to which we contribute five interaction techniques. Two are inspired by literature: Virtual Magic Lens and Binary Transition; while the other three are entirely novel: Auto Blended Space, Manual Blended Space - Button Transition and Manual Blended Space - Touch Transition. In a study evaluating the first four techniques, we found that participants (N=20) performed a CR object manipulation and transition task significantly faster using our Auto Blended Space technique. We then modified Manual Blended Space - Button Transition into Manual Blended Space - Touch Transition in response to these results, and reassessed the four techniques in a more complex object manipulation task (N=16). We found that this type of task was better suited to manual transition methods rather than automatic methods. Taken together, our final contribution are five blended space design factors, and timely Cross-Reality transition design guidelines.

When establishing a visual connection between a virtual reality user and an augmented reality user, it is important to consider whether the augmented reality user faces a surplus of information. Augmented reality, compared to virtual reality, involves two – not one – planes of information: the physical and the virtual. We propose SelectVisAR, a selective visualisation system of virtual environments in augmented reality. Our system enables an augmented reality spectator to perceive a co-located virtual reality user in the context of four distinct visualisation conditions: Interactive, Proximity, Everything, and Dollhouse. We explore an additional two conditions, Context and Spotlight, in a follow-up study. Our design uses a human-centric approach to information filtering, selectively visualising only parts of the virtual environment related to the interactive possibilities of a virtual reality user. The research investigates how selective visualisations can be helpful or trivial for the augmented reality user when observing a virtual reality user.

We present two use cases of mobile displays in cross-reality interactions between users immersed in Virtual Reality (VR) and users present in the Physical Reality (PR) by using the mobile display to show select artefacts of interest. The first use case is the “Substitutional Display” where a display serves as a passive haptic for an artefact. Both VR and PR users can then move the artefact by physically moving the display. The second use case is a “Virtual Artefact Handover” which allows the VR user to pass artefacts onto the PR user’s display. We envision this handover as a natural interaction where the VR user moves the artefact onto a virtual proxy of the display the PR user is holding, after which the artefact is displayed for the PR user to see.