From: John Wann Subject: Re: HUMAN-FACTORS: SIDs & HMDs Date: Tue, 8 Oct 1996 15:30:18 +0000 Message-ID: Ed Lantz wrote: >Decisions are usually made in groups. A >group of engineers in a realtime CAD design review wearing HMD's are >terribly isolated from one another and all have different points of view. > If you are using a SID for group experience there can only be 1 "driver", who controls the viewpoint goemetry and for all those who aren't at the "sweet-spot" the projection geometry is incorrect. (e.g. someone sat infront of or behind the driver, sees the scale slightly compressed or extended). SIDS present geometrically incorrect images for groups and this is a fundamental flaw if it was being used for a precise working environment. This also raises a problem of how the "group" interact with the database - with an HMD system a single member can move round to view something from a different perspective - In a SID this is not possible without perspective distortion, you have to let the "driver" take you around. > >Keep in mind that commercial SID systems are young and have not yet been >optimized for low cost. "SimCenters" are emerging which lease time on >these systems making them (potentially) profitable. Even if the cost of projectors does plummet, then you still can't get round the requirement of a large dedicated space, and if the only option is booking time downtown, then this is fine to demo the product to your CEO, but not for a day-to-day visualisation aid. >You are mixing apples (low end HMDs) with oranges (high-end SIDs). For >starters, a $3,000 HMD is probably giving you less than VGA resolution. No not apples and oranges - just different types of apple - as the price of projectors reduces, then the resolution of low-cost HMDs goes up - its the same technology feeding both, eventually the two will converge in $-per-pixel, and it will depend on what type of application-requirement you have and for hospital/health-care sectors I think HMD systems should have the edge. >frankly, many of these corporations view HMD's as toys or lab curiosities >as far as their >applications are concerned. Thats my concern - I really have no issue with what you're saying about SIDs being useful for corporate sectors, and I'm not proposing that 5 execs should sit in a conference with HMDs on. But there is a real role for HMDs in design/visualisation where there are 1 or 2 participants working together. A number of VR protagonists are eager to extol the virtues of the CAVE etc.. without also considering its limitations. I think it would be a pity if the impetus was lost from the HMD market because the influential parties in "corporate VR" are pushing SIDs ********************************************************* Dr John P. Wann < J.P.Wann@rdg.ac.uk> ********************************************************** Action Research Laboratory: Development, Rehabilitation, Immersive Virtual Environments (Wann, Mon-Williams, Langaas, Smyth , Swapp, Wallis, Wadsworth) Supported by: Action Research; EPSRC: European Commission ARL - DRIVE Department of Psychology University of Reading PO Box 238, Reading RG6 6AL, UK +44 1734 318532 Fx +44 1734 316604 ***********************************************************