In the realm of virtual reality (VR), shape-changing controllers have emerged as a means to enhance visuo-haptic congruence during user interactions. The major emphasis has been placed on manipulating the inertia tensor of a shape-changing controller to control the perceived shape. This paper delves deeper by exploring how the material properties of the controller's handle, distinct from the inertial information, affect the perceived shape, focusing on the perceived length. We conducted three perceptual experiments to examine the effects of the handle's softness, thermal conductivity, and texture, respectively. Results demonstrated that a softer handle increases the perceived length, whereas a handle with higher thermal conductivity reduces it. Texture, in the form of varying bumps, also alters the length perception. These results provide more comprehensive knowledge of the intricate relationship between perceived length and controller handle properties, expanding the design alternatives for shape-changing controllers for immersive VR experiences.
doi.org/10.1145/3613904.3642251
This paper explores the feasibility of deliberately designing VR motion that diverges from users’ physical movements to turn mundane, everyday transportation motion (e.g., metros, trains, and cars) into more entertaining VR motion experiences, in contrast to prior car-based VR approaches that synchronize VR motion to physical car movement exactly. To gain insight into users’ preferences for veering rate and veering direction for turning (left/right) and pitching (up/down) during the three phases of acceleration (accelerating, cruising, and decelerating), we conducted a formative, perceptual study (n=24) followed by a VR experience evaluation (n=18), all conducted on metro trains moving in a mundane, straight-line motion. Results showed that participants preferred relatively high veering rates, and preferred pitching upward during acceleration and downward during deceleration. Furthermore, while veering decreased comfort as expected, it significantly enhanced immersion (p<.01) and entertainment (p<.001) and the overall experience, with comfort being considered, was preferred by 89% of participants.
doi.org/10.1145/3613904.3642064
We introduce InflatableBots, shape-changing inflatable robots for large-scale encountered-type haptics in VR. Unlike traditional inflatable shape displays, which are immobile and limited in interaction areas, our approach combines mobile robots with fan-based inflatable structures. This enables safe, scalable, and deployable haptic interactions on a large scale. We developed three coordinated inflatable mobile robots, each of which consists of an omni-directional mobile base and a reel-based inflatable structure. The robot can simultaneously change its height and position rapidly (horizontal: 58.5 cm/sec, vertical: 10.4 cm/sec, from 40 cm to 200 cm), which allows for quick and dynamic haptic rendering of multiple touch points to simulate various body-scale objects and surfaces in real-time across large spaces (3.5 m x 2.5 m). We evaluated our system with a user study (N = 12), which confirms the unique advantages in safety, deployability, and large-scale interactability to significantly improve realism in VR experiences.
doi.org/10.1145/3613904.3642069
Virtual reality (VR) objects react dynamically to users' touch interactions in real-time. However, experiencing changes in weight through the haptic sense remains challenging with consumer VR controllers due to their limited vibrotactile feedback. While prior works successfully applied pseudo-haptics to perceive absolute weight by manipulating the control-display (C/D) ratio, we continuously adjusted the C/D ratio to mimic weight changes. Vibrotactile feedback additionally emphasises the modulation in the virtual object's physicality. In a study (N=18), we compared our multimodal technique with pseudo-haptics alone and a baseline condition to assess participants' experiences of weight changes. Our findings demonstrate that participants perceived varying degrees of weight change when the C/D ratio was adjusted, validating its effectiveness for simulating dynamic weight in VR. However, the additional vibrotactile feedback did not improve weight change perception. This work extends the understanding of designing haptic experiences for lightweight VR systems by leveraging perceptual mechanisms.
doi.org/10.1145/3613904.3642552
Dedicated handheld controllers facilitate haptic experiences of virtual objects in mixed reality (MR). However, as mobile MR becomes more prevalent, we observe the emergence of controller-free MR interactions. To retain immersive haptic experiences, we explore the use of mobile devices as a substitute for specialised MR controller. In an exploratory gesture elicitation study (n = 18), we examined users' (1) intuitive hand gestures performed with prospective mobile devices and (2) preferences for real-time haptic feedback when exploring haptic object properties. Our results reveal three haptic exploration modes for the mobile device, as an object, hand substitute, or as an additional tool, and emphasise the benefits of incorporating the device's unique physical features into the object interaction. This work expands the design possibilities using mobile devices for tangible object interaction, guiding the future design of mobile devices for haptic MR experiences.
doi.org/10.1145/3613904.3642176