Haptics in the Metaverse: Haptic feedback for Virtual, Augmented, Mixed, and eXtended Realities

In the last few years, we have witnessed the rapid development of many innovative devices and original techniques for providing haptic sensations, e.g., using force feedback, mid-air interfaces, props and encounter-type devices, or exploiting perceptual phenomena with cross-modal effects such as pseudo-haptics. While increasingly immersive and realistic experiences have developed at a fast pace, the emergence of a “metaverse” proposes new use cases where prolonged utilisation and social interactions become more frequent and widespread. The metaverse definition is continuously evolving, however, for now it can been seen as a collective virtual shared space, created by the convergence of the physical and digital worlds, where users interact, socialize, and engage with each other through digital representations of themselves. This new direction in social interactions presents the haptics community with new challenges and opportunities. Indeed, as eXtended Reality (XR) technologies continue to gain traction in various fields, the role of haptic feedback and feedforward in enhancing such experiences have become increasingly evident. This growing significance is reflected in the proliferation of research efforts and the emergence of dedicated haptic designs, tools, and rendering techniques. Never before have tactile actuators found such proliferation in 3D applications, akin to that experienced in the early days of smartphones.

This special issue is dedicated to exploring the multifaceted realm of haptics tailored to XR environments, including Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR). The collection of studies presented here represents a diverse array of topics and approaches, each contributing to our fundamental understanding of haptics in the context of such immersive technologies. Some of the featured research found in this special issue delves into the theoretical foundations of haptics in XR, unveiling the complexities of human haptic perception, touch, and proprioception. Understanding how users perceive and interact in virtual environments is paramount to crafting truly immersive experiences that mimic the sense of touch and presence of the real world. In parallel, other contributions focus on the practical aspects of haptic interface design, exploring new methods, principles, and guidelines to create more effective and intuitive haptic interactions. These studies aim to strike a delicate balance between providing realistic touch sensations and ensuring comfortable, ergonomic, and user-friendly haptic devices. A significant portion of this special issue is dedicated to the advancements in haptic actuation and sensing technologies. From traditional vibrotactile actuators to more sophisticated systems like ultrasound, electrostatic, piezoelectric, and magnetic actuators, researchers have been striving to create more versatile, precise, and responsive haptic feedback mechanisms that align seamlessly with multimodal and multisensory virtual and augmented realities. Finally, as XR technologies find applications in a wide range of industries, this special issue showcases novel haptic approaches tailored to specific domains. Whether it be industrial training or artistic expression, these studies demonstrate the adaptability of haptic interfaces to diverse applications and contexts.

We believe that the research presented in this special issue will not only advance our knowledge of haptics in XR, but will also inspire further innovation and foster cross-disciplinary collaborations. As technology continues to push the boundaries of what is possible in the realm of virtual and augmented reality, haptic interfaces will play an increasingly pivotal role in shaping the future of immersive (social) experiences.

We have received many exceptional submissions for this special issue, indicating the research community’s profound enthusiasm for haptics in such a field. Our gratitude goes to the Editors in Chief, Domenico Prattichizzo, Seungmoon Choi, and Marcia K. O’Malley, for their support to the success of this topic. Additionally, we extend our heartfelt appreciation to the numerous reviewers who contributed highquality and timely reviews. Lastly, we would like to express our thanks to Shivam Sony, a member of the ToH editorial staff, for his precious assistance throughout the publication process. We hope that this collection of 14 research papers will serve as a valuable resource for researchers, practitioners, and enthusiasts, driving us all closer to a more haptically enriched virtual and augmented world.