Abstract
Virtual Reality is becoming more popular over the years because it allows the user to be the main actor in another environment and interact with it in real time. New interaction methods are being studied, like tangible interfaces, but there is little work done related to small distances when grabbing objects through a virtual environment. This study is important because, in our perspective, interaction in virtual reality will be at arms reach, meaning that the user will interact within very close distances (under 1 m). In this paper, the research team further evaluate distance perception using gender, the presence of avatar and height (fixed or personalised). The sample consisted of 64 participants (32 females and 32 males) evenly distributed between all four conditions (8 males and 8 females for each condition). Results revealed that gender does have an impact on small distance estimation; height does not have an impact on distance estimation; and avatar does make a difference when trying to grab a real object through the virtual environment. © Springer Nature Switzerland AG 2019.

Abstract
Although selection menus are widely used for interaction, their use on 3D virtual reality applications needs to be objectively assessed. The focus of this study is to evaluate a traditional panel and a radial menu in two distinct virtual environment placements (i.e. fixed on the wall and following the users' hands). Fifty-one participants used two different menus of the four possible combinations. To evaluate the menus' effectiveness and efficiency, we measured usability (System Usability Scale Questionnaire), user satisfaction (After-Scenario Questionnaire), time to finish the tasks (in seconds) and the number of unnecessary steps (errors) performed by the users. Overall results showed a clear preference for the traditional panel menu type and the fixed wall placement of the menu. We conclude that all menu types perform well, despite different user preferences, and that fixing the menu to the wall gives users a better overview of both the menu and the virtual environment, improving their ability to perceive their actions on the menu.

Abstract
In the original publication, Figs. 1 and 2 were interchange and the citation of Fig. 1 in the third paragraph of section 2.2 Authoring tools for multisensory VR experiences should be removed.

Abstract
Virtual Reality (VR) technologies have evolved to the point where it is being used in various areas (entertainment, medicine, education, etc.). One of the metrics that allow the evaluation of the virtual experience is Presence. In this work, we conduct an exploratory study that studies which factors of VR games correlate to presence. Various components of games are also shared between other VR applications allowing the results to be applicable not only in VR games. A study with 78 participants divided into 5 groups was conducted where each group played a different VR game. Presence and Game Experience were evaluated. The results indicated multiple positive correlations between subscales of Presence and Game Experience.

Abstract
Innovations in virtual reality have boosted their use for business purposes and personal consumption. The main objective of this technology is to transport the user to virtual environments. The use of avatars to replace the user's body in these environments increases the levels of presence and embodiment of the user. Through the inverse kinematics it is possible to animate the avatars according to the data obtained in sensors scattered around the user's body, replicating the movements in a avatar. These sensors can vary in number offering different levels of fidelity in the tracking of the human body. In this paper, we study the impact of the number of sensors used in the presence of the user and in the embodiment of the avatar, using three, five and six tracking points. The results show that there is no statistically significant differences in presence nor in any of its sub-scale, however one can observe a positive trend in the 6-points conditions. As for embodiment, the results show that there is statistically signifficant differences in some of presence sub-scales, namelly tactile sensation, response and in the embodiment as a whole.

Abstract
Hands are the most important tool to interact with virtual environments, and they should be available to perform the most critical tasks. For example, a surgeon in VR should keep his/her hands on the instruments and be able to do secondary tasks without performing a disruptive event to the operative task. In this common scenario, one can observe that hands are not available for interaction. The goal of this systematic review is to survey the literature and identify which hands-free interfaces are used, the performed interaction tasks, what metrics are used for interface evaluation, and the results of such evaluations. From 79 studies that met the eligibility criteria, the voice is the most studied interface, followed by the eye and head gaze. Some novel interfaces were brain interfaces and face expressions. System control and selection represent most of the interaction tasks studied and most studies evaluate interfaces for usability. Despite the best interface depending on the task and study, the voice was found to be versatile and showed good results amongst the studies. More research is recommended to improve the practical use of the interfaces and to evaluate the interfaces more formally.