From: pepke@ds1.scri.fsu.edu (Eric Pepke) Subject: Re: Motion Sickness and VR Date: 24 Jan 91 05:41:35 GMT Organization: Florida State University, but I don't speak for them In article <14998@milton.u.washington.edu> LHETTINGER@FALCON.AAMRL.WPAFB.AF.MIL writes: >flight simulator sickness. I would also suggest a sixth potential cause: >head movements. Any motion of the head made in the presence of conflicting >visual information for self motion (i.e., the eyes "specify" rotational >motion, the inner ears "specify" some different motion) may serve to enhance >the conflict. Whatever the cause - excessive head movements often lead to >trouble with sickness. I thought what I said included this. The semicircular canals are definitely part of the nonvisual perception that needs to be squared with visions. Excessive head movements can cause another thing entirely--they can make the fluid slosh around in such a way that it has no longer anything to with reality and cannot be predicted. (Hmmm... I wonder what would happen if one were to model the head tilt sensors after semicircular canals?) >>1 and 2 are very easily solved. Just make the viewed orientation an accurate >>representation of the actual orientation. > >I think this is a reasonable suggestion for some VR settings - for flight >simulators, though, I don't think it will work. To link the simulator >dynamics to head dynamics would violate the training purposes of the device. You're right. I am specifically thinking about forms of virtual reality where emulation of an actual physical environment is not important. I'm thinking of sort of an idealized reality, for the same reason that I don't think my Macintosh "desktop" needs to have coffee stains. Personally, I think that if you're going to have a flight simulator, you should at least spring for one of those virtual roller coasters that run on hydraulics (the cheaper ones on motors and worm gears) one sees in all the malls. It'll set you back a lot less than what the VPL guys will soak you for. >Well, I don't think you want to ignore this because it's still a >visual-vestibular conflict situation and therefore can't be ruled out as >potentially contributing to disorientation and sickness. This may also be a >potential use for a dynamic seat of some sort. I just thought of another potential solution (again, only in my kind of VR). The only reason that we need to make really sharp turns in the world is that things are fixed in their coordinate system. Why not, when I turn, warp the positions of distant objects so that a perceptually small turn over a large distance generates a big turn? Incidentally, a while back for my day job I implemented a way of flying around a dataset in a visualization package I'm working on. I wound up emulating the dynamics of some sort of idealized airplane because it seemed to feel the most natural. I'm not sure why, as I've only flown an airplane a couple of times for short periods, but maybe it's because the dynamics are similar to riding a bicycle. The more I think about, the more I want to approach reality like a salad bar-- take what I like and leave the rest. My VR house can look like a physical entity, but why can't it be on Pepke block of Name street and Eric block as well? Why shouldn't it be on the intersection of an arbitrarily large number of streets, name street and occupation street and hat size street? Why shouldn't it have an address in Jazztown and Nerdville and Punk City and the red light district as well? Why shouldn't it be tardis-like on the inside? The trick and the challenge is to abstract the feelings of reality in such a way that they still work but don't have the same constraints. Eric Pepke INTERNET: pepke@gw.scri.fsu.edu Supercomputer Computations Research Institute MFENET: pepke@fsu Florida State University SPAN: scri::pepke Tallahassee, FL 32306-4052 BITNET: pepke@fsu Disclaimer: My employers seldom even LISTEN to my opinions. Meta-disclaimer: Any society that needs disclaimers has too many lawyers.