A Few Notes on Virtual Reality

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Nov 14, 2013 (3 years and 7 months ago)

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A Few Notes on Virtual Reality

Glenn G. Chappell

CHAPPELLG@member.ams.org

U. of Alaska Fairbanks


CS 381 Lecture Notes

Friday, October 17, 2003

17 Oct 2003

CS 381

2

Notes on VR:

Presence


A typical 2½
-
D GUI simulates a desktop.


Users look at
pictures

of objects reminiscent
of overlapping sheets of paper.


Typical 3
-
D interfaces give the user a
picture

of a 3
-
D world.


Games, etc.


In virtual reality (VR), we want to give
users the sense that they are
inside

a
computer
-
generated world.


In VR this is called the sense of
presence
.

17 Oct 2003

CS 381

3

Notes on VR:

How Do We Create “Presence”?


Immersion


Fill the user’s vision with CG, so that very little of the real world can
be seen.


Stereoscopic

Perspective


Produce different perspective views for each eye, giving the illusion
of depth.


Head/Eye Tracking


Track the position & orientation of the user’s head or eyes, so that
we can draw the scene from the correct point of view.


Multisensory Output


Engage as many of the user’s senses as we can, in a coordinated,
realistic, 3
-
D manner.


Plausible Interaction


Allow the user to interact with the scene, in as direct a manner as
possible, in a way that “feels right”.

17 Oct 2003

CS 381

4

Notes on VR:

VR Display Types [1/2]


Two flavors of VR displays: Theater & Head
-
Mounted.


Theater


This is what we have.


Most modern theater
-
type VR displays are based on the
“CAVE”.


CAVE

= CAVE Automatic Virtual Environment.


See also Plato (
The Republic
, Book 7).


Developed at the Electronic Visualization Laboratory, at the U. of
Illinois Chicago, in 1992.


Advantages



Allows for multiple simultaneous users (in a limited sense).


Allows immersion, but can still see the real world
if you want
.


So you don’t trip over things.


Disadvantages



Cost.


Portability.


Stereoscopic display requires fancy hardware.

17 Oct 2003

CS 381

5

Notes on VR:

VR Display Types [2/2]


Head
-
Mounted Display (HMD)


Put one display right in front of each eye, and a tracker
somewhere on the user’s head.


Advantages



Cost.


Size.


Disadvantages



Heavy stuff to wear on your head.


Physical hazards (tripping, etc.).


Latency problems!



Latency

= time to update the display.


What happens when you move your head and the display update is
slow? Contrast this with theater
-
type VR.


In my opinion, HMD’s are the future of VR. However, truly
usable HMD’s are not available (yet). When they are, VR can
finally go mass
-
market.

17 Oct 2003

CS 381

6

Notes on VR:

Other Stuff


We know how to handle sight and hearing. But what about:


Balance


Tilt the theater. Simple, but bulky & expensive. Done in flight simulators.


Touch


Haptic

interfaces are those that involve touch.


Possible on a small scale (desktop?), but not a large scale (Discovery Lab).


Smell? Taste???


Forget it (for now).


Augmented Reality


Real world + CG additions.


HMD without the tripping problem?


The Focus Problem


In VR displays, near & far objects are drawn on the same screen.


Objects appear to be at varying distances, but the eye always
focuses

at the same distance.


Result: headaches.


Go solve this problem!

17 Oct 2003

CS 381

7


The remainder of the class meeting
was taken up by demonstrations of
VR research projects, primarily:


BLUIsculpt (VR sculpting application)


Experimental sound generation