From: Robert W. Lindeman [gogo@SEAS.GWU.EDU]
Sent: Tuesday, August 03, 1999 11:17 AM
To: Jeff Pierce
Cc: 3d-ui@hitl.washington.edu
Subject: Re: Idea for discussion: violating assumptions

On Tue, 3 Aug 1999, Jeff Pierce wrote:

Hi Jeff,

Interesting ideas. I had a lot of fun reading them (aside: maybe one of
the asumptions you are trying to break is that research is laborious, and 
no fun.. ;-) I can think of one thing that commonly violates 
assumptions...

Objects have substance
  - Turn off collision detection (if it was ever turned on).

To turn things on their head, I would argue that many (most?) interfaces
routinely violate assumptions. Which brings me to another point. There is
also the notion of the source of the assumptions. Some come from the
physical laws, some abstract ones come from the things we have learned
by using GUIs, and some from other technologies, like 
telephones/televisions. Anyway, I guess I'm just trying to say that it
might be important to look at the source of the assumptions.

Here are some comments:
(For clarity, I've snipped out the ones I'm not commenting on.)

> The Assumptions
> ---------------
> 
> So, getting right to it, this section lists the assumptions I've come up
> with so far and both potential and existing techniques that break
> those assumptions.  Not all of the techniques are useful (heck, some
> are downright ludicrous), but at this point the idea is just to brainstorm
> many as possible.  Existing techniques start with a -, new (as far as I know) 
> techniques with a *.  Some of the descriptions are
> very terse; if you're curious ask me for more details.  Some of the
> techniques also violate multiple assumptions.
> 
> 
> 1) Space is linear and continuous.  To move a foot you walk a foot,
> and you can't move from A to B without traversing the space in between.
> 
> - teleportation
> * a room larger inside than outside
> * guiding movement / navigation
> 	- an infinite corridor or series of corridors that provide
> 	immediate backtracking
> 	- different length paths that meet
> - Head Crusher navigation
> * Telescope navigation
> * Magnifying glass object manipulation
> * Non-linear transmission of light and sound
> 	- distant rooms where users can hear each other
> 	- one-way sound/light transmission
> 	- allowing user to see places normally not visible

(I think some of your things from #5 below could fit here too. The thread
being non-linearity).
- The Go-Go technique(s)
- Mine's work with scaled-world-grab

> 5) Size of objects remains constant
> 
> - Head crusher
> - Mine's world scaling
> - Go-Go
> - SmartScene
> * World compression ball

As I said above, I think this fits mostly with the linearity construct.

> 6) Gravity
> 
> - flying

- Hovering
(Physics in general is routinely ignored.)

> 9) The world we perceive really is 3D
> 
> * pulling away current view as 2D image to reveal another reality
> * "pop up" worlds that user can fold up and put away

- Web pages?

> 13) The occluded side of an object does not change when it's out of
> view
> 
> * imagine an infinite storage container like a dry-cleaner's rack
> where continued rotation just brings more objects into view
> 	- object sphere -> rotate toward an object on a (visible) edge
> 	to get "more like me"
> 
> - rotating an object to turn it into something else
> 	- didn't Mine do this in ISAAC for widgets?

This is like an elevator with unlimited floors. (Wasn't this a Star Trek
episode? ;-)

> 15) The world exists even when it's not in view
> 
> - culling to speed up rendering
> - simulating only objects in view to speed up simulation

You could extend this to mean that objects can change when they are not
in view. "If a tree falls in the forest..." Once you look away from an
object, it might have a different shape when you look at it again.

Others I can think of:
a) Your avatar looks like you
   - "On the Internet, no one knows you're a dog."
b) You only have 2 hands
   * Can we activate/manipulate multiple (>2) hands?
c) All objects are oriented alike, wrt the UP vector.
   - Why is it that all Star Trek ships always meet with the same UP
     vecotr?

Some thoughts...
1) It might be a good idea to insure reliability, if not predictability.
What I mean is that an interface should act *consistently* if it is to be
usable. It can still be fun (and powerful), but it needs to be usable.
(Unless your goal is pure fun, of course).

2) It is difficult to tell if you are looking at:
   a) Navigation,
   b) Maneuvering,
   c) Object manipulation,
   d) General interaction, or
   e) Fun and Mayhem.


Anyway, that's all I can come up with right now. As I said before,
interesting stuff! I look forward to seeing what you come up with, and how
you focus this down to thesis size ;-)

-Rob

---
         _/     _/     _/     _/  * Robert W. Lindeman, Sc.D.
_/_/  _/  _/ _/  _/ _/  _/ _/  _/ * Institute for Computer Graphics
       _/_/   _/     _/_/   _/    * The George Washington University
        _/            _/          * email: gogo@seas.gwu.edu
   _/_/_/        _/_/_/           * http://tangle.seas.gwu.edu/~gogo/