###### Abstract  
The affordability of equipment and availability of development tools have made immersive virtual reality (VR) popular across research fields. Gesture-based user interface has emerged as an alternative method to handheld controllers to interact with the virtual world using hand gestures. Moreover, a common goal for many VR applications is to elicit a sense of presence in users. Previous research has identified many factors that facilitate the evocation of presence in users of immersive VR applications. We investigated the user experience of Four Seasons, an immersive virtual reality simulation where the user interacts with a natural environment and animals with their hands using a gesture-based user interface (UI). We conducted a mixed-method user experience evaluation with 21 Korean adults (14 males, 7 females) who played Four Seasons. The participants filled in a questionnaire and answered interview questions regarding presence and experience with the gesture-based UI. The questionnaire results indicated high ratings for presence and gesture-based UI, with some issues related to the realism of interaction and lack of sensory feedback. By analyzing the interview responses, we identified 23 potential presence factors and proposed a classification for organizing presence factors based on the internal-external and dynamic-static dimensions. Finally, we derived a set of design principles based on the potential presence factors and demonstrated their usefulness for the heuristic evaluation of existing gesture-based immersive VR experiences. The results of this study can be used for designing and evaluating presence-evoking gesture-based VR experiences. immersive virtual reality; gesture-based interface; presence; user experience; mixed-method user study +
Footnote †: journal: Medical  
not limited to, the quality of information [9; 10], user control [10; 11], realism [10], and certain cognitive, emotional, and behavioral factors [10; 12]. High-quality equipment (e.g., HMD, controllers, motion trackers) and the correctness of the code that orchestrates the VR experience may contribute to eliciting presence. These are examples of presence factors, which we define as any element of a VR system or its usage context that has a positive effect on eliciting presence. Gesture-based interactions have been studied since the early days of VR [13; 14; 15] to make the use of VR technology more comfortable and natural. In a gesture-based interface, physical gestures such as hand movements are used to interact with a computer system. A gesture-based interface is a popular instantiation of the broader concept of a natural user interface (NUI), which can be used to realize the transparency of the interface in HMD-based VR. Factors that facilitate presence in VR have previously been studied [9; 10; 11; 12; 16; 17]; however, studies on presence in the context of gesture-based UI are lacking. Identifying factors that may affect presence in VR by utilizing a gesture-based UI can be helpful when designing future immersive experiences. Therefore, we investigated the user experience of an immersive VR experience that utilizes gesture-based UI from the perspectives of presence and gesture-based interaction. The target gesture-based VR experience is called Four Seasons, and it was designed to provide an engaging and relaxing experience in a natural environment simulation. We formulated the following research questions and sought answers to them:  
1. How do users perceive the gesture-based UI of Four Seasons? 2. What potential presence factors can be associated with Four Seasons? To answer the research questions, we conducted a mixed-method user experience evaluation of the Four Seasons VR experience based on a questionnaire and interview data gathered from 21 adult participants.