Date: Thu, 22 Nov 2001 22:58:14 -0500 From: "Wolfgang Stuerzlinger" Subject: Re: 2D interfaces in a 3D environment Sender: To: "Jeff Pierce" Cc: "3D UI list" <3d-ui@hitl.washington.edu> Message-id: <3BFDC956.92ADF0F1@cs.yorku.ca> Organization: Dept. of Computer Science, York University MIME-version: 1.0 X-Mailer: Mozilla 4.7 [en] (Win98; U) Content-type: text/plain; charset=iso-8859-1 Content-transfer-encoding: 7BIT Importance: Normal X-MSMail-Priority: Normal X-Accept-Language: en X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 References: <3BF9D3A2.5E8EA9C@home.com> <4.1.20011121135214.00bc4100@ux2.sp.cs.cmu.edu> X-Authentication-warning: torch.hitl.washington.edu: majordom set sender toowner-3dui@hitl.washington.edu using -f X-Priority: 3 (Normal) Jeff Pierce wrote: > > At 09:12 AM 11/21/01, Wolfgang Stuerzlinger wrote: > >Taking this argument one step further one can use what most people percieve > >as normal or "common sense" (e.g. that gravity exists :-) and use this to > >simplify interactions even further. This improves interaction speed by > >a factor of approximately 2.5. See the papers on the MIVE system > >on my WWW page. > > Improves interaction speed for what task? There are some obvious examples > (manipulation of objects at a distance, navigating large distances) where > using what people perceive as normal (or, more accurately, familiar) is > much, much slower than using a "magic" technique. True. However, I would like to point out that even "magic" techniques can benefit from "common sense". Take e.g. a 6 DOF tracker, where the tracker position & orientation are used to do ray-casting for one of many interaction-at-a-distance techniques. Users expect e.g. a distant house to stay flat on the ground when it is moved around, yet the 6DOF tracker makes this practically impossible, due to rotation around the ray axis. "Common sense", be it implemented as gravity or as an "on-floor" constraint, will make a lot of difference even in this case. > And as a minor point, I can posit virtual worlds where you _don't_ want > gravity. Why on earth would I want things to fall to the floor if I > accidentally drop them? It'd be much easier if they hovered within reach > so that I could grab them again. I care to disagree. My experience with taking people "off-the-street" into VR environments is that they don't like objects floating in the air in essentially arbitrary positions & orientations. One issue here is that floating objects often block the view of other objects, which hinders people. Another is that the orientation of the object makes it often inconvenient to further manipulate the object. More importantly, people working in zero-g (astronauts) don't leave things floating in space, even though they could theoretically. They attach objects as much as possible onto surfaces or other objects to keep things surveyable and to maximize space for moving around. But yes, I do agree that it sounds good to just "hang something into the air" and there are some interesting uses of this (e.g. Mark Mine's over-the-shoulder delete/recover idea). I just think that floating objects is a bad choice for the system-wide default in VR systems/toolkits. Wolfgang -- Wolfgang Stuerzlinger Dept. of Computer Science; York University CCB 3048; 4700 Keele Street; Toronto, Ontario, M3J 1P3; Canada wolfgang@cs