Worlds-in-Miniature (WiMs) are interactive worlds within a world and combine the advantages of an input space, a cartographic map, and an overview+detail interface. They have been used across the extended virtuality spectrum for a variety of applications. Building on an analysis of examples of WiMs from the research literature we contribute a design space for WiMs based on seven design dimensions. Further, we expand upon existing definitions of WiMs to provide a definition that applies across the extended reality spectrum. We identify the design dimensions of size-scope-scale, abstraction, geometry, reference frame, links, multiples, and virtuality. Using our framework we describe existing Worlds-in-Miniature from the research literature and reveal unexplored research areas. Finally, we generate new examples of WiMs using our framework to fill some of these gaps. With our findings, we identify opportunities that can guide future research into WiMs.
In virtual reality (VR) environments, asymmetric bimanual interaction techniques can increase users' input bandwidth by complementing their perceptual and motor systems (e.g., using the dominant hand to select 3D UI controls anchored around the non-dominant arm). However, it is unclear how to optimize the layout of such 3D UI controls for near-body and mid-air interactions. We evaluate the performance and limitations of non-dominant arm-anchored 3D UIs in VR environments through a bimanual pointing study. Results demonstrated that targets appearing closer to the skin, located around the wrist, or placed on the medial side of the forearm could be selected more quickly than targets farther away from the skin, located around the elbow, or on the lateral side of the forearm. Based on these results, we developed Armstrong guidelines, demonstrated through a Unity plugin to enable designers to create performance-optimized arm-anchored 3D UI layouts.
JetController is a novel haptic technology capable of supporting high-speed and persistent 3-DoF ungrounded force feedback. It uses high-speed pneumatic solenoid valves to modulate compressed air to achieve 20-50Hz of full impulses at 4.0-1.0N, and combines multiple air propulsion jets to generate 3-DoF force feedback. Compared to propeller-based approaches, JetController supports 10-30 times faster impulse frequency, and its handheld device is significantly lighter and more compact. JetController supports a wide range of haptic events in games and VR experiences, from firing automatic weapons in games like Halo (15Hz) to slicing fruits in Fruit Ninja (up to 45Hz). To evaluate JetController, we integrated our prototype with two popular VR games, Half-life: Alyx and Beat Saber, to support a variety of 3D interactions. Study results showed that JetController significantly improved realism, enjoyment, and overall experience compared to commercial vibrating controllers, and was preferred by most participants.
Virtual Reality experiences, such as games and simulations, typically support the usage of bimanual controllers to interact with virtual objects. To recreate the haptic sensation of holding objects of various shapes and behaviors with both hands, previous researchers have used mechanical linkages between the controllers that render adjustable stiffness. However, the linkage cannot quickly adapt to simulate dynamic objects, nor it can be removed to support free movements. This paper introduces GamesBond, a pair of 4-DoF controllers without physical linkage but capable to create the illusion of being connected as a single device, forming a virtual bond. The two controllers work together by dynamically displaying and physically rendering deformations of hand grips, and so allowing users to perceive a single connected object between the hands, such as a jumping rope. With a user study and various applications we show that GamesBond increases the realism, immersion, and enjoyment of bimanual interaction.
Game designers and researchers employ a sophisticated language for producing great player experiences with concepts such as juiciness, which refers to excessive positive feedback. However, much of their discourse excludes the role and value of haptic feedback. In this paper, we adapt terminology from game design to study haptic feedback. Specifically, we define haptic embellishments (HEs) as haptic feedback that reinforce information already provided through other means (e.g., via visual feedback) and juicy haptics as excessive positive haptic feedback with the intention of improving user experience in games and other interactive media. We report two empirical studies of users' experiences interacting with visuo-haptic content on their phones to 1) study participants' preferences for ten design principles for HEs and 2) measure the added value of juicy haptics, implemented as HEs, on player experience in a game. Results indicate that juicy haptics can enhance enjoyability, aesthetic appeal, immersion, and meaning.
Current head-mounted displays enable users to explore virtual worlds by simply walking through them (i.e., real-walking VR). This led researchers to create haptic displays that can also simulate different types of elevation shapes. However, existing shape-changing floors are limited by their tabletop scale or the coarse resolution of the terrains they can display due to the limited number of actuators and low vertical resolution. To tackle this challenge, we introduce Elevate, a dynamic and walkable pin-array floor on which users can experience not only large variations in shapes but also the details of the underlying terrain. Our system achieves this by packing 1200 pins arranged on a 1.80 x 0.60m platform, in which each pin can be actuated to one of ten height levels (resolution: 15mm/level). To demonstrate its applicability, we present our haptic floor combined with four walkable applications and a user study that reported increased realism and enjoyment.
Numerous techniques have been proposed for locomotion in virtual reality (VR). Several taxonomies consider a large number of attributes (e.g., hardware, accessibility) to characterize these techniques. However, finding the appropriate locomotion technique (LT) and identifying gaps for future designs in the high-dimensional space of attributes can be quite challenging. To aid analysis and innovation, we devised Locomotion Vault (https://locomotionvault.github.io/), a database and visualization of over 100 LTs from academia and industry. We propose similarity between LTs as a metric to aid navigation and visualization. We show that similarity based on attribute values correlates with expert similarity assessments (a method that does not scale). Our analysis also highlights an inherent trade-off between simulation sickness and accessibility across LTs. As such, Locomotion Vault shows to be a tool that unifies information on LTs and enables their standardization and large-scale comparison to help understand the space of possibilities in VR locomotion.
Smartphone touch screens are potentially attractive for interaction in virtual reality (VR). However, the user cannot see the phone or their hands in a fully immersive VR setting, impeding their ability for precise touch input. We propose mounting a mirror above the phone screen such that the front-facing camera captures the thumbs on or near the screen. This enables the creation of semi-transparent overlays of thumb shadows and inference of fingertip hover points with deep learning, which help the user aim for targets on the phone. A study compares the effect of visual feedback on touch precision in a controlled task and qualitatively evaluates three example applications demonstrating the potential of the technique. The results show that the enabled style of feedback is effective for thumb-size targets, and that the VR experience can be enriched by using smartphones as VR controllers supporting precise touch input.
Selection and manipulation in virtual reality often happen using an avatar's hands. However, objects outside the immediate reach require effort to select. We develop a target selection technique called Ninja Hands. It maps the movement of a single real hand to many virtual hands, decreasing the distance to targets. We evaluate Ninja Hands in two studies. The first study shows that compared to a single hand, 4 and 8 hands are significantly faster for selecting targets. The second study complements this finding by using a larger target layout with many distractors. We find no decrease in selection time across 8, 27, and 64 hands, but an increase in the time spent deciding which hand to use. Thereby, net movement time still decreases significantly. In both studies, the physical motion exerted also decreases significantly with more hands. We discuss how these findings can inform future implementations of the Ninja Hands technique.
Augmented Reality (AR) is increasingly being used for providing guidance and supporting troubleshooting in industrial settings. While the general application of AR has been shown to provide clear benefits regarding physical tasks, it is important to understand how different visualization types influence user’s performance during the execution of the tasks. Previous studies evaluating AR and user’s performance compared different media types or types of AR hardware as opposed to different types of visualization for the same hardware type. This paper provides details of our comparative study in which we identified the influence of visualization types on the performance of complex machine set-up processes. Although our results show clear advantages to using concrete rather than abstract visualizations, we also find abstract visualizations coupled with videos leads to similar user performance as with concrete visualizations.
Interacting with out of reach or occluded VR objects can be cumbersome. Although users can change their position and orientation, such as via teleporting, to help observe and select, doing so frequently may cause loss of spatial orientation or motion sickness. We present vMirror, an interactive widget leveraging reflection of mirrors to observe and select distant or occluded objects. We first designed interaction techniques for placing mirrors and interacting with objects through mirrors. We then conducted a formative study to explore a semi-automated mirror placement method with manual adjustments. Next, we conducted a target-selection experiment to measure the effect of the mirror's orientation on users' performance. Results showed that vMirror can be as efficient as direct target selection for most mirror orientations. We further compared vMirror with teleport technique in a virtual treasure hunt game and measured participants’ task performance and subjective experiences. Finally, we discuss vMirorr user experience and present future directions.
Tactile feedback is widely used to enhance realism in virtual reality (VR). When touching virtual objects, stiffness and roughness are common and obvious factors perceived by the users. Furthermore, when touching a surface with complicated surface structure, differences from not only stiffness and roughness but also surface height are crucial. To integrate these factors, we propose a pin-based handheld device, HairTouch, to provide stiffness differences, roughness differences, surface height differences and their combinations. HairTouch consists of two pins for the two finger segments close to the index fingertip, respectively. By controlling brush hairs' length and bending direction to change the hairs' elasticity and hair tip direction, each pin renders various stiffness and roughness, respectively. By further independently controlling the hairs' configuration and pins' height, versatile stiffness, roughness and surface height differences are achieved. We conducted a perception study to realize users' distinguishability of stiffness and roughness on each of the segments. Based on the results, we performed a VR experience study to verify that the tactile feedback from HairTouch enhances VR realism.
For haptic guidance, vibrotactile feedback is a commonly-used mechanism, but requires users to interpret its complicated patterns especially in 3D guidance, which is not intuitive and increases their mental effort. Furthermore, for haptic guidance in virtual reality (VR), not only guidance performance but also realism should be considered. Since vibrotactile feedback interferes with and reduces VR realism, it may not be proper for VR haptic guidance. Therefore, we propose a wearable device, GuideBand, to provide intuitive 3D multilevel force guidance upon the forearm, which reproduces an effect that the forearm is pulled and guided by a virtual guider or telepresent person in VR. GuideBand uses three motors to pull a wristband at different force levels in 3D space. Such feedback usually requires much larger and heavier robotic arms or exoskeletons. We conducted a just-noticeable difference study to understand users’ force level distinguishability. Based on the results, we performed a study to verify that compared with state-of-the-art vibrotactile guidance, GuideBand is more intuitive, needs a lower level of mental effort, and achieves similar guidance performance. We further conducted a VR experience study to observe how users combine and complement visual and force guidance, and prove that GuideBand enhances realism in VR guidance.