Comparison of One-handed and Two-handed Text Entry in Virtual Reality Using Handheld Controllers
Authors: Hassan Ali , Mackenzie Scott , Sohn Gunho 
Published: June 2023

Current consumer virtual reality (VR) systems rely heavily on handheld controllers for input. To this end, numerous methods have been developed and investigated since the emergence of VR in order to improve the user experience for interactions such as gaming or text entry while wearing a head-mounted display (HMD) and using handheld controllers [1, 2]. Although several novel text entry methods have been proposed, there is little research comparing the methods using virtual keyboard interfaces evaluated as experimental conditions. This would allow for a more focused and specialized comparison.Statement of Objective:This work presents the design and empirical evaluation of a split and standard virtual keyboard for text input in virtual environments using handheld controllers. There are numerous applications, including games, for example, entering a gamer’s name or messaging other gamers. An experimental evaluation of two virtual keyboards using VR handheld controllers will be conducted. (Note: As the experiment is ongoing, this abstract is written in the future tense. The final submission will transition to the past tense.) The focus will be on entry speed, accuracy, and efficiency. Both keyboards will be QWERTY-based, but with different organizations. Similar to most physical keyboards, the “standard” keyboard will have all the keys in one arrangement. However, the “split” keyboard will display keys in a split pattern on each side of the screen. For the standard keyboard, users will operate one handheld controller in their preferred hand. For the split keyboard, users will operate one controller in each hand. Thus, a significant point of comparison in the present research is one-handed input vs. two-handed input for the same task. Description of Methods:This research follows an experimental methodology. There will be a total of 14 participants recruited from the local university campus. The study will be a 2 × 5 within-subjects design with the following independent variables and levels:• Keyboard (standard one-handed, split two-handed)• Block (1, 2, 3, 4, 5)The order of testing the keyboards will be counterbalanced to offset learning effects.Five phrases of text will be entered for each block, with phrases selected at random from a standard phrase set [3]. Thus the total number of trials will be 14 participants x 2 keyboards x 5 blocks x 5 phrases/block = 700. The following are the dependent variables in the study:• Entry speed (wpm)• Error rate (%)• Keystroke per character (KSPC)The Unity 3D game engine is used to create the text-input interface installed on the Meta Quest 2 VR headset. Participants will use the Meta Quest handheld controllers to input text. Input uses raycasting, in which the handheld controller casts a virtual line or ray. The virtual ray is positioned on a key on the virtual keyboard, wherein the user presses the trigger on the handheld controller to select the character indicated by the ray.Significance of the Proposed Presentation:The work is significant due to its presentation of the design and experimental evaluation of novel text entry input methods for virtual environments The work pushes the limits of contemporary devices (Meta Quest 2 VR headset) and platforms (Unity 3D game engine) into a design space of particular interest to research in virtual environments.Discussion of Results:Statistical tests, such as the analysis of variance, will be used to identify statistically significant differences between the keyboards for entry speed (wpm), error rate (%), and efficiency using KSPC. Tests for improvement in performance over the five blocks of testing will be included, as well. Regression models will be built using the power law of practice to model the pattern of learning over the blocks of testing. Design implications and suggestions will be offered, as will opportunities for future work. Full details are to be included in the final submission.