Head-mounted displays increasingly require text entry that goes beyond character input to support real-world writing and editing. Existing HMD text entry research and systems focus primarily on entry speed and accuracy, while offering limited support for cursor control, navigation, and command execution. Midair and voice-based techniques address some needs but suffer from fatigue, limited affordances, and poor discoverability of editing functions. This work investigates one-handed thumb-to-finger text composition for HMDs, combining on-body input with hand-proximate visual interfaces that provide tactile feedback and spatial guidance. We map the design space of such systems across input, editing, command invocation, and visualization. Through participatory design workshops with 18 designers, we elicit concrete concepts for one-handed text composition on HMDs. From these artifacts, we derive five implementable design guidelines focused on discoverability and complex text composition.

Shape-changing displays typically lose pixel density as surface area expands, limiting their usability. We introduce MorphSkein, a shape-changing after-image display that preserves initial density (1.44 px/cm 2 ) across naturally occurring axisymmetric shapes generated by spinning cables (troposkeins). The system uses a telescopic pole and four LED-strip rewinders on a rotating base. As the strips spin, centrifugal force forms troposkeins, and persistence of vision creates 360°-visible displays, while adjusting pole height and strip lengths changes their shape. As surface area grows, pixel density is preserved vertically by releasing new rows from the rewinders and horizontally by rendering extra columns per revolution with the strips. This keeps comparable density along the central horizontal line of the display, with naturally higher density toward the top and bottom where the troposkein curves inward. Because the technique relies on a mathematical model assuming ideal troposkein geometry, angular velocity becomes critical: incorrect speeds degrade pixel density accuracy, axisymmetric shape fidelity, or both. Interpolation of experimental data shows that 69.44% of reachable troposkein configurations achieve ⩾90% density accuracy and shape fidelity for at least one operating speed. Remaining cases degrade due to insufficient motor speed or limited MCU speed and LED refresh rate. Limitations and improvements are discussed.

Hand Proximate User Interfaces (HPUI) on Head Mounted Displays (HMD) leverage hand tracking to anchor content on the hand and interact with it using thumb-to-finger interactions. Similar to many other interaction techniques on HMDs, HPUI realizes these interactions by combining simple geometry in game engines. This, in turn, leads to accidental triggers, akin to the "fat-finger problem" on touch screens. To address this, we explore and provide insight into how the thumb’s surface interacts when using HPUI by approximating the thumb’s surface with a large number of raycasts. We observe that different regions of the thumb are used when interacting with different parts of the hand. The results also highlight the need to consider the temporal component. We then propose approaches to improving the precision of thumb-to-finger interactions on HPUI and show that these improve target selection accuracy with denser target layouts.

Designing a comfortable, familiar, and efficient one-handed text entry method for Head-Mounted Displays (HMDs) remains a significant challenge. Existing midair typing systems induce fatigue, while novel techniques often demand extensive training or sacrifice input efficiency. Consequently, we introduce ThumbSwype , a novel thumb-to-finger text entry technique that adapts smartphone swipe typing for HMDs. Users see the traditional QWERTY keyboard overlaid on their index, middle, and ring fingers, allowing them to perform swipe gestures with their thumb to type words. In an evaluation study (N=16) , participants achieved a mean of 14.52 words per minute (WPM), which is 63.8% of their smartphone swipe-typing performance, with a peak average of 20.2 WPM. We compare ThumbSwype’s performance with related work, and discuss directions for future improvement.

We explore the value of Hand Proximate User Interfaces (HPUIs) for in-situ interactive head-mounted systems, i.e. systems designed to support a user’s primary activity. HPUIs are unencumbered, single-handed, and have tactile and proprioceptive affordances. This allows novice and expert users to rely on the visual cues available in the UI, but to then gradually interact eyes-free such that they minimize interrupting the user’s core task. Prior work on HPUI falls short of validating this premise. We address this gap with comparative analysis in the context of a compound task, where one hand is involved in a primary task and the second interacts with a secondary but supporting task (e.g. selecting items from a menu). We compare HPUI with mid-air direct interactions, a common form of interacting with head-mounted displays. The results show that HPUI performs similarly to mid-air but with better eyes-free affordances and user preferences.

Head Mounted Displays (HMDs) are gaining more public attention. With the advancement of tracking technologies, they are incorporating unencumbered interaction techniques to address the need for user-friendly and efficient interaction techniques for day-to-day activities. While there is a good understanding of the different interaction techniques individually, very little research has been done to compare them directly. This would be vital to understanding their strengths and weaknesses in different contexts and building better synergies among them. This paper uses a target selection task to compare the performance and user preferences for four interaction techniques: gaze-pinch, ray pointer, hand-proximate user interface, and direct mid-air interactions. Results indicate that the gaze-pinch interaction technique required significantly more time to complete the task than the others, whose time to complete was similar. However, in terms of preferences and errors, the interaction techniques mostly performed similar.

Our study investigates the design practices of Hand-Proximate User Interfaces (HPUI) which are displayed on and around a user’s hand in a head-mounted display (HMD). Specifically, we examine one-handed inputs where the main mode of interaction is thumb-to-finger contact. Our focus is on the user interface (UI) design of these displays, and we aim to develop design guidelines and heuristics for this novel design space. To achieve this, we conducted a participatory design study involving 15 participants who provided feedback on 120 different design examples, as well as their thoughts surrounding the HPUI design. Participants favored designs that were ergonomically comfortable and flexible, and those that provided clear visibility regardless of hand positioning. Based on this feedback, we developed 7 design guidelines for Hand Proximate User Interfaces. In applying these guidelines we find that common application interfaces can easily be accommodated using HPUI for use on head-mounted displays.

Three state virtual keyboards which differentiate contact events between released, touched, and pressed states have the potential to improve overall typing experience and reduce the gap between virtual keyboards and physical keyboards. Incorporating force sensitivity, three-state virtual keyboards can utilize a force threshold to better classify a contact event. However, our limited knowledge of how force plays a role during typing on virtual keyboards limits further progress. Through a series of studies we observe that using a uniform threshold is not an optimal approach. Furthermore, the force being applied while typing varies significantly across the keys and among participants. As such, we propose three different approaches to further improve the uniform threshold. We show that a carefully selected non-uniform threshold function could be sufficient in delineating typing events on a three-state keyboard. Finally, we conclude our work with lessons learned, suggestion for future improvements, and comparisons with current methods available.

We present EdgeSelect, a linear target selection interaction technique that utilizes a small portion of the smartwatch display, explicitly designed to mitigate the ‘fat finger’ and screen occlusion problems, two of the most common and well-known challenges when interacting with small displays. To design our technique, we first conducted a user study to answer which segments of the smartwatch display have the least screen occlusion while users are interacting with it. We use results from the first experiment to introduce EdgeSelect, a three-layer non-linear interaction technique, which can be used to interact with multiple co-adjacent graphs on the smartwatch by using a region that is the least prone to finger occlusion. In a second experiment, we explore the density limits of the targets possible with EdgeSelect. Finally, we demonstrate the generalizability of EdgeSelect to interact with various types of content.

We present BezelGlide, a novel suite of bezel interaction techniques, designed to minimize screen occlusion and ‘fat finger’ effects, when interacting with common graphs on smartwatches. To explore the design of BezelGlide, we conducted two user studies. First, we quantified the amount of screen occlusion experienced when interacting with the smartwatch bezel. Next, we designed two techniques that involve gliding the finger along the smartwatch bezel for graph interaction. Full BezelGlide (FBG) and Partial BezelGlide (PBG), use the full or a portion of the bezel, respectively, to reduce screen occlusion while scanning a line chart for data. In the common value detection task, we find that PBG outperforms FBG and Shift, a touchscreen occlusion-free technique, both quantitatively and subjectively, also while mobile. We finally illustrate the generzability potential of PBG to interact with common graph types making it a valuable interaction technique for smartwatch users.

We explore the design of Hand Proximate User Interfaces (HPUIs) for head-mounted displays (HMDs) to facilitate near-body interactions with the display directly projected on, or around the user's hand. We focus on single-handed input, while taking into consideration the hand anatomy which distorts naturally when the user interacts with the display. Through two user studies, we explore the potential for discrete as well as continuous input. For discrete input, HPUIs favor targets that are directly on the fingers (as opposed to off-finger) as they offer tactile feedback. We demonstrate that continuous interaction is also possible, and is as effective on the fingers as in the off-finger space between the index finger and thumb. We also find that with continuous input, content is more easily controlled when the interaction occurs in the vertical or horizontal axes, and less with diagonal movements. We conclude with applications and recommendations for the design of future HPUIs.