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Realtime 3D Computer Graphics Virtual Reality Marc Erich Latoschik AI & VR Lab Artificial Intelligence Group University of Bielefeld Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik Virtual Reality (or VR for short)… …can be defined as … …an artificial environment which is experienced through sensory stimuli (as sights and sounds) provided by a computer and in which one's actions partially determine what happens in the environment (Merriam Webster) …a human-computer interface which -by addressing several senses- lets us perceive a computer generated environment as reality. (based on Alexander Hennig "Die andere Wirklichkeit (the other reality)“) …the simulation of a real or imagined environment that can be experienced visually in the three dimensions of width, height, and depth and that may additionally provide an interactive experience visually in full real-time motion with sound and possibly with tactile and other forms of feedback. …(and many more)

Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

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Page 1: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

Realtime 3D Computer GraphicsVirtual Reality

Marc Erich Latoschik

AI & VR Lab

Artificial Intelligence Group

University of Bielefeld

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

Virtual Reality (or VR for short)…

…can be defined as …

• …an artificial environment which is experienced through sensory stimuli (as sights and sounds) provided by a computer and in which one's actions partially determine what happens in the environment (Merriam Webster)

• …a human-computer interface which -by addressing several senses- lets us perceive a computer generated environment as reality. (based on Alexander Hennig "Die andere Wirklichkeit (the other reality)“)

• …the simulation of a real or imagined environment that can be experienced visually in the three dimensions of width, height, and depth and that may additionally provide an interactive experience visually in full real-time motion with sound and possibly with tactile and other forms of feedback.

• …(and many more)

Page 2: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

The term(s) of Virtual Reality

• Phantomology or phantomatic

• is introduced by Stanislav Lem as a concept of artificial realities in his Summa Technologiae (Lem, 1964) and in several publications since then.

• Virtual Reality

• This term is attributed to Jaron Lanier of VPL in 1986 in a conversation regarding the work of Scott Fisher.

• Virtual Environments

• is how Fisher, of NASA Ames, had been referring to the field.

• Artificial Reality

• is a label for such activities by Myron Krueger in 1983.

• Cyberspace

• This term is coined by William Gibson in his book Neuromancer (Gibson, 1984).

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR Flavors

• Artificial RealityUser is observer of an artificial environment, uses an avatar as a placeholder for the user.

• Augmented RealityMerges reality with Virtual Reality. Naturally and artificially generated stimulus is overlapped and complements each other.

• CyberspaceEmphasizes the network related parts of and artificial computer generated environment.

• Immersive Virtual RealityEmbeds the user psycho-physically into the artificial surrounding. User merges into the generated environment.

Page 3: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR characteristics1

1. immersion: To submerge into simulated space.

2. multidimensionality: Used to create space.

3. real-time: Simulation is processed in real-time.

4. adequacy: Movement results in an appropriate simulation change.

5. interaction: Users can interact with the environment.

6. navigation: Movement in the simulated space (as would be possible in reality).

7. reality-effect: To perceive the artificial surrounding as real and believable.

8. multi-user: Multiple users can enter the virtual space and communicate and interact.

1following (Bühl, 1997)

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR - simulating stimuli

Phantomologyperipheralexternal sensation source

centraldirect

brain excitation

Sense: a system that consists of a sensory cell type (or group of cell types) that respond to a specific kind of physical energy, and that correspond to a defined region (or group of regions) within the brain where the signals are received and interpreted (Wikipedia)

• VR is simulation of stimuli for human senses.

• No agreement about the number of actual senses (at least 9).

• The better the simulation the higher is the degree of immersion.

Page 4: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

• W

...residual self image......mental projection of digital self...

...what is real?

...electrical signals interpreted by your brain...

...see......taste......smell.....feel..

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR - simulating stimuli

reality

virtuality

hear

ingsight

touch

tastesmell

Simulating stimuli:

• VR simulates stimuli to 5 main senses (following Aristotle)

• Senses are gradually simulated to bridge reality and virtuality.

• The different VR-flavors stimulate

• different senses to

• different degrees.

central phantomology

peripheral phantomology

Immersive Virtual Reality

Non-immersive

Virtual Reality

Pre-virtual worlds

CMC, mediazationde

g.

of

imm

ers

ion

sight

Page 5: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR and the notion of space

• Simulating sensual stimuli is done by setting certain parameters (to generate stimuli).

• Every parameter defines a one dimensional range of possible values.

• Combining several parameters for the same stimulated sense creates a “sense space” For example:

• R,G,B (or HIS, HSV etc.) parameters open a color space.

• Sweet, sour, salty, bitter, umami parameters open a gustatory (taste) space.

• Pitch, volume and duration open a sound space.

• X, Y, Z (or length, height and width) open an 3D (possibly Euclidian) space.

1following (Bühl, 1997)

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

VR and the notion of space

• Perceptual (mental) Space

• Important aspect in philosophy and cognitive science.

• Things appear extended because they have the attributes of color and solidity (David Hume).

• has a projective geometry, things within it appear as if they are viewed from a point (Rene Descarte).

• Projective geometry might describe the layout of things in perception (Peters, 2000).

1following (Bühl, 1997)

Page 6: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

Simulation of sensory stimuli• VR is about the simulation of sensory stimuli which fake stimuli sensed in the

real physical world.

• The human sensory systems consists of several sub-systems all with their own features and modes of operation, e.g.• sensed space(s)

• processing speed

• processing resolution

• processing accuracy

• Stimulation of a certain sensory system requires to take that system’s mode of operation into account.

• For example: • The simulation of tactile feedback (haptics) requires a much higher simulation rate

as the simulation of visual stimuli.

• The resolution of the auditory sense is different then the resolution of the visual sense.

! Creating visual stimuli is considered critical for immersive VR. This is followed by tactile and auditory and then by olfactory and gustatory simulation.

Realtime 3D Computer Graphics / Virtual Reality – WS 2005/2006 – Marc Erich Latoschik

Space: creating visual stimuli

• Visual stimuli are a major source for the perception of space.

• Simulating the surrounding virtual space of users is the goal.

• VR utilizes real-time 3D computer graphics (CG) to create visual stimuli.

Conventional 3D CG in contrast to VR:

3D Computer Graphics Virtual Reality

Purely visual presentation Multimedia presentationvisual, acoustic, haptic,…

Presentation can be rendered off-line, time is uncritical

Real-time presentation

Static scenes or predefined animations

Real-time interaction and simulation

2D interaction

mouse, keyboard

3D interaction with special input devices + speech (and gesture)

Page 7: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality

AI & VR Lab: Virtual Biosphere II

AI & VR Lab: Virtual Biosphere II

Page 8: Virtual Reality (or VR for short)É - Technische Fakultät · Virtual Reality Pre-virtual worlds CMC, mediazation deg. of immersion. Realtime 3D Computer Graphics / V irtual Reality