MetaSpace II (MS2) is a social Virtual Reality (VR) system where multiple users can not only see and hear but also interact with each other, grasp and manipulate objects, walk around in space, and get tactile feedback. MS2 allows walking in physical space by tracking each user’s skeleton in realtime and allows users to feel by employing passive haptics i.e., when users touch or manipulate an object in the virtual world, they simultaneously also touch or manipulate a corresponding object in the physical world. To enable these elements in VR, MS2 creates a correspondence in spatial layout and object placement by building the virtual world on top of a 3D scan of the real world. Through the association between the real and virtual world, users are able to walk freely while wearing a head-mounted device, avoid obstacles like walls and furniture, and interact with people and objects. Most current virtual reality (VR) environments are designed for a single user experience where interactions with virtual objects are mediated by hand-held input devices or hand gestures. Additionally, users are only shown a representation of their hands in VR floating in front of the camera as seen from a first person perspective. We believe, representing each user as a fullbody avatar that is controlled by natural movements of the person in the real world (see Figure 1d), can greatly enhance believability and a user’s sense immersion in VR.
 The study explored the impact of physically touching a virtual object on how realistic the VE seems to the user. Subjects in a "no touch" group picked up a 3D virtual image of a kitchen plate in a VE, using a traditional 3D wand. "See and touch" subjects physically picked up a virtual plate possessing solidity and weight, using a mixed-reality force feedback technique. Afterwards, subjects made predictions about the properties of other virtual objects they saw but did not interact with in the VE. "See and touch" subjects predicted these objects would be more solid, heavier, and more likely to obey gravity than the "no touch" group. Results provide converging evidence for the value of adding physical qualities to virtual objects. The study first empirically demonstrates the effectiveness of mixed reality as a simple, safe, inexpensive technique for adding physical texture and force feedback cues to virtual objects with large freedom of motion. Examples of practical applications are discussed. We present Virtual Notepad, a collection of interface tools that allows the user to take notes, annotate documents and input text using a pen, while still immersed in virtual environments (VEs). Using a spatially-tracked, pressure-sensitive graphics tablet, pen and handwriting recognition software, Virtual Notepad explores handwriting as a new modality for interaction in immersive VEs. This paper reports details of the Virtual Notepad interface and interaction techniques, discusses implementation and design issues, reports the results of initial evaluation and overviews possible applications of virtual handwriting. This paper reports empirical results from a study into the useof 2D widgets in 3D immersive virtual environments. Severalresearchers have proposed the use of 2D interaction techniques in3D environments, however little empirical work has been done totest the usability of such approaches. We present the results oftwo experiments conducted on low-level 2D manipulation tasks withinan immersive virtual environment. We empirically show that theaddition of passive-haptic feedback for use in precise UImanipulation tasks can significantly increase user performance.Furthermore, users prefer interfaces that provide a physicalsurface, and that allow them to work with interface widgets in thesame visual field of view as the objects they are modifying.