Reaching out to grasp in Virtual Reality : A qualitative usability evaluation of interaction techniques for selection and manipulation in a VR game

Abstract: A new wave of VR head mounted displays is being developed and released to the commercial market including examples such as the HTC Vive, Oculus Rift and Playstation VR. Bundled together with these head mounted displays are a new generation of hand motion controllers which allows the users to reach out and grasp in the virtual environment. Earlier research has explored a range of possible interaction techniques for immersive VR interaction, mainly focusing on the quantitative and objective performance of each technique. Yet even with this research picking the right technique for a given scenario remains a challenging task. This study tries to complement earlier research by instead investigating the qualitative and more subjective aspects of usability, along with making use of the upcoming commercial VR hand controllers. The purpose was to provide guidelines to help future immersive VR interaction designers and researchers. Two interaction techniques (classic Go-Go and ray casting with a reel) were chosen to represent the two most commonly used interaction metaphors for selection and manipulation, i.e. grabbing and pointing. Eleven users were then recruited to try the two interaction techniques inside a shopping scene initially part of a commercial VR game. Each user had to complete five tasks for each technique while “thinking aloud”, followed by an interview after the test. The sessions were recorded and analysed based on five usability factors. The results indicated a strong preferences for the Go-Go interaction technique, with arguments based on how natural its interaction was. These results confirmed several conclusions drawn in earlier research about interaction in immersive VR, including the strength of natural interaction in scenarios which has the capacity to reach a high grade of naturalism, as well as the importance of showing the user when the interaction technique differs from realistic behaviour. Last but not least the results also pointed to the importance of further study on immersive VR interaction techniques over long time use and when combined with user interfaces.