The vergence-accommodation conflict (VAC) limits user performance in current Virtual Reality (VR) systems. In this paper, we investigate the effects of the VAC in a single-focal VR system using three experimental conditions: with no VAC, with a constant VAC, and with a varying VAC. Previous work in this area had yielded conflicting results, so we decided to re-investigate this issue. Eighteen participants performed an ISO 9241:411 task in a study that closely replicates previous work, except that the angle of the task space was rotated 20 degrees downward, to make the task less fatiguing to perform, which addresses a potential confound in previous work. We found that the varying VAC condition had worse performance than the other conditions, which indicates that the contrasting results in previous work were very likely due to biomechanical factors. We hope that our work contributes to the understanding of the influence of the VAC in VR systems and potential strategies for improving user experience and performance in immersive virtual environments.

During the complex process of motor skill acquisition, novices might focus on different criteria, such as speed or accuracy, in their training. Previous research on virtual reality (VR) has shown that effective throughput could also be used as an assessment criterion. Effective throughput combines speed, accuracy, and precision into one measure, and can be influenced by auditory feedback. This paper investigates through a user study how to improve participants’ effective throughput performance using auditory feedback. In the study, we mapped the speed and accuracy of the participants to the pitch of the auditory error feedback in an ISO 9241-411 multidirectional pointing task and evaluated participants’ performance. The results showed it is possible to regulate the time or accuracy performance of the participants and thus the effective throughput. Based on the findings of our work, we also identify that effective throughput is an appropriate assessment criterion for VR systems. We hope that our results can be used for VR applications.

In eye-gaze-based selection, dwell suffers from several issues, e.g., the Midas Touch problem. Here we investigate saccade-based selection techniques as an alternative to dwell. First, we designed a novel user interface (UI) for Actigaze and used it with (goal-crossing) saccades for confirming the selection of small targets (i.e., < 1.5-2°). We compared it with three other variants of Actigaze (with button press, dwell, and target reverse crossing) and two variants of target magnification (with button press and dwell). Magnification-dwell exhibited the most promising performance. For Actigaze, goal-crossing was the fastest option but suffered the most errors. We then evaluated goal-crossing as a primary selection technique for normal-sized targets (≥ 2°) and implemented a novel UI for such interaction. Results revealed that dwell achieved the best performance. Yet, we identified goal-crossing as a good compromise between dwell and button press. Our findings thus identify novel options for gaze-only interaction.

In this paper, we present a virtual training platform for soldering based on immersive visual feedback (i.e., a Virtual Reality (VR) headset) and scaffolded guidance (i.e., disappearing throughout the training) provided through a haptic device (Phantom Omni). We conducted a between-subject user study experiment with four conditions (2D monitor with no guidance, VR with no guidance, VR with constant, active guidance, and VR with scaffolded guidance) to evaluate their performance in terms of procedural memory, motor skills in VR, and skill transfer to real life. Our results showed that the scaffolded guidance offers the most effective transitioning from the virtual training to the real-life task — even though the VR with no guidance group has the best performance during the virtual training. These findings are critical for the industry and academy looking for safer and more effective training techniques, leading to better learning outcomes in real-life implementations. Furthermore, this work offers new insights into further haptic research in skill transfer and learning approaches while offering information on the possibilities of haptic-assisted VR training for complex skills, such as welding and medical stitching.