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)
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.
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.
• 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
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)
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)
AI & VR Lab: Virtual Biosphere II
AI & VR Lab: Virtual Biosphere II
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