From: Pierre duPont Subject: Re: DESIGN: Body models in VE Date: Fri, 29 Mar 1996 20:08:05 +-100 >In VE there are several ways in which we can represent the user's body >to him/herself. For example, we can create a fully-tracked body model >or fix an image of a hand at the bottom of the screen as in Doom. Does >anybody know of any research that has looked at the performance >effects of having vs. not having such body representations? Thanks >Jenny Ehrlich >jae28485@pegasus.cc.ucf.edu ----- Jenny - I don't have any proper research to support this, but I've got a lot of subjective experience with which to answer. But first, if you fix your virtual hand somewhere on the screen, then you're probably not talking about immersive VR, and thus you've got a world of difference right there, compared to head/hand tracking with an immersive system. These two are wildly different in user-performance, and they each can be considered 'better' in certain circumstances and for certain tasks. If you stick to just immersive VR (and for me this means head-tracked with some kind of HMD, and hand-tracked) then a more interesting question becomes: what's the performance comparison of having your tracked (and thus free-to-move-anywhere) hand represented *without* a joining arm, vs. with an articulated joining arm back to your shoulder? Here we find that having the arm helps a lot - it makes you more comfortable overall, and it helps you understand where your hand really is, undoubtedly because the perspective-convergent arm gives you an additional depth cue. However, the arm can be detrimental too, because without a very large field-of-view in your HMD, the arm can obscure a higher percentage of the overall display area than you are used to. The rest of the body isn't so important, since without an exceptionally large field-of-view in your HMD, you'll only rarely see the rest of your body anyway. Although .... If you happen to have two VR systems lying around (:-), and can network them together, then the rest of the body is absolutely essential, even if it does nothing more than 'hang' from the head. To explain this, consider that we do a lot of "head stuffing" at exhibitions and so on - e.g., giving demos to hundreds of people who just want to "have a look". Often we find that, for someone who has never been inside an immersive VR system before, there can be a few minutes of less-than-optimal performance before the "newbie" gets it figured out - before they acclimate and become comfortable with movement and interaction inside the virtual environment. I think this initial learning period is well documented elsewhere. At our last few tradeshows, we've had two VR systems networked together, and we used one for head-stuffing and the other as an experienced "teacher" in the same virtual environment. Both users were head- and hand-tracked, and were represented by articulated bodies. Having that teacher present and with an articulated body made a tremendous difference to the newbie. We found that the initial learning period nearly totally vanished. Of the several hundred demos we've given with the second user as a teacher, we've found almost no instances of the traditional newbie acclimation period - the presence and guidance of the teacher made the newbie learn to navigate and interact much more quickly. A body (with as much tracking and articulation as possible) is essential for the teacher. - Pierre duPont, Division dupontp@division.co.uk