VR%20Technologies%20

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VR Technologies Collaborative Virtual
EnvironmentsKaj GrønbækIntermedia Department
of Computer ScienceUniversity of Aarhusemail
kgronbak_at_intermedia.au.dk

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Content of talk

• Intro to Virtual Reality (VR)
• Collaborative Virtual Environments
• Deeper dive into some Collaborative VE systems
• DIVE
• MASSIVE
• Discussion
• Possibility for DIVE Demo

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What is Virtual Environments?

• Different kinds of artificial micro worlds -
  often 3D worlds
• Main distinctions in virtual reality
• immersive and non-immersive
• physical or psycologically immersed
• The Internet per se and MUDs (Multi User
  Dungeons) are considered as VR by some
• MUDMulti-User Dungeons
• Similar to a text based rolleplay or adventure
  game
• MOO MUD Object Oriented
• WebMOO WOO
• Roles in a MUD are predecessors for Avatars
• Avatars liverepresentations of the user in
  cyberspace
• Teleportation - move of an avatar from one place
  to another

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Applications of VR technology

• Visualisering af ideer og fantasier om noget nyt
• Digital prototyping
• Industrial design
• Architechture
• Inspection and instruction in use of complex and
  dangerous enviroments
• Nuclear powerplants
• Oil rigs
• Vessels

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Concepts and trends

• From Virtual Reality to a mixture of physical
  and virtual worlds
• Mixed reality
• Augmented reality
• From single user experience to support for
  collaboration
• From Head Mounted Displays to projection based VR
• Multiple VR installations coupled via network

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Display technology

• Computer graphics (3D models)
• Polygon models (e.g.VRML)
• Picture-based (e.g. Quicktime VR)
• Ray tracing, Splines
• Stereo effect
• With special (shutter) glasses
• Immersiveness
• Fully immersive
• Goggles, gloves, force feedback, CAVEs
• Medium immersive
• Responsive workbench, visual domes, reality rooms
• Non immersive
• MUDs, MOOs, WOOs, Internet, VRML, CAD etc
• Reality, augmented reality, mixed reality,
  augmentedvirtuality, virtual reality

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Traditional VR - Goggles and gloves

• Fully immersive
• Local communication and collaboration is
  difficult
• Simulation and training
• Entertainment
• Poor interaction with other people

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Communication and collaboration

• Collaboration
• at the same place, at the same time
• at different places, same time
• at different places, different times
• Meet in virtual shared spaces
• Non-immersive
• MUDs, MOOs, WOOs, Internet
• Immersive
• Videolink, Teleport
• Collaborate about the models

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Projection Based VR

• Wall size projections
• Polarized glasses
• Shutter glasses

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Depth Perception

• MonoSame image for both eyesOnly monocular
  depth cues

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Depth Perception

• Stereo, Binocular Depth Individual images for
  left and right eye
• Objects may be seenin front oforbehindthe
  projection screen

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Stereo techniques

• Passive stereo
• Two projectors at 60 Hz
• Polarised light
• Polarised glasses
• Simultaneous projection of the two images

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Stereo techniques

• Active stereo
• One projector at 120 Hz
• Alternating projection of the two images
• Shutter-glassessyncronised by IR-signal

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Display Systems - 3D workbenches

• Mono active stereo
• Tracking available
• Two-handed interaction
• Max 5 people - 1 perfect view

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Responsive Workbench

• Medium immersive
• Higly interactive
• Collaboration
• Between people at the same place
• Between remotely separated people?
• Simulation, training, Construction, Medical
  training

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Display Systems - Panorama

• Panorama
• Ø 7.1m, 160, H 3.5m
• Mono active stereo
• 28 observers max.
• Tracking available

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Reality Rooms (Panoramas)

• Medium immersive
• No interaction
• Presentations and entertainment
• Collboration and communication for larger
  communities?

Copy from TRIMENSION
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Display Systems - CAVE

• CAVE
• 2.5m by 2.5m by 2.5m
• Back projection
• Active stereo
• 1 observer with tracking, few observers without

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Immersive Environments (CAVE)

• Higly immersive
• Higly interactive
• Dynamically change model
• Collaboration
• Between people at the same place
• Between remotely separated people
• Simulation, training, architecture, design
• Entertainment

The name CAVE is a trademark in the USA (and
only in the USA) by UICU/EVL
Copy from TAN
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Immersive Environments (CAVE)
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Interaction

• Flying, walking, teleporting, object picking,
  changing model
• Speech, gestures and further human expressions
• Sensors, trackers, gloves, glasses, special
  devices
• Force feedback, heating
• Mouse, 3D mouse
• Pt. Relative to one person

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Visual Dome

• Medium immersive
• No interaction
• Presentations
• Entertainment
• Collboration and communication for larger
  communities?

Copy from TRIMENSION
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Teleport
Higly immersive? Higly interactive? Collaboration
Between remotely reparated people Distance
education, distributed meetings
Copy from GMD
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Infinity wall

• Higly immersive?
• Higly interactive?
• Collaboration
• Between remotely separated people
• Distance education, distributed meetings

Copy from EVL
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Tanorama

• Simulation, training

Copy from TAN
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Simulation

• Better and rapid understanding og complex
  phenomena
• fluid dynamics, crash simulation
• Cheaper than real-life training
• Simulations which could not be performed in real
  life
• the Vasa ship

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Quicktime VR

• Non-immersive
• Interactive
• Communication
• Depending on the application
• Visualisation, simulation, education, museums,
  entertainment

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Collaborative virtual environments

• CVE can support collaboration among several users
  dispersed or co-located in space
• Collaborators are embodied in the shared space
• CVE mainly support Common Object Spaces
• SVE is well-suited for collaboration about models
  of 3D artifacts of any kind
• Houses, cars, oil-rigs, powerplants, models of
  human bodies,
• But also textual discussions in MOOs
• CVE may incorporate traditional information
  sources on shared whiteboards or similar
• Some CVEs allow users to create and leave
  objects in the shared space

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CVE on the Internet - VRML

• VRML stands for Virtual Reality Modelling
  Language
• Originally Virtual Reality Markup Language
• An interpreted standardized language (ISO/IEC
  14772) for 3D virtual worlds, which can be
  interlinked and used via the Web
• VRML uses the existing Web infrastructure
• VRML is experienced through a web browser
• Plug-Ins or Viewers embedded in Netscape
  Communicator (e.g. CosmoPlayer)
• Stand-Alone Browsers Webspace, Scuba
• VRML 2.0 spec
• http//www.vrml.org/Specifications/VRML2.0/FINAL/s
  pec/index.html
• Lots of examples on http//vrml.sgi.com

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VRML 2.0 Browser

• SGIs CosmoPlayer
• Plug-in for Netscape available for Windows 95,
  Windows NT and SiliconGraphics
• Support for fast interaction with large 3D worlds
  
• Hypermedia support by means of WWW links
• Integration of VRML Java HTML MM

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VRML features

• Rendering Generation of photorealistic pictures
  based on model
• Linking coupling of partial worlds with
  hypermedia-links á la WWW
• Constructs programs (e.g. Java or CGI) which
  manipulate worlds
• Sensing Detection of events e.g. collisions
• Server multicast simultaneous updates of worlds
• Scripting partial worlds can be sent as
  parameters to programs that make relevant
  transformations
• Sound 3D sound and background sound
• Sensors mechanisms for the user to interact with
  objects
• Animations moving worlds by means of keyframes
• Routing events reactions to user generated
  events can be routed between objects

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Collaboration on design models via WWW and VRML
Collaboration Server (Event distribution)
Object server
www.vreality.dk
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Internet based collaborative virtual environments

• MASSIVE-1 and 2, from Nottingham
• DIVE from SICS in Sweden
• Both systems provide
• Integration of tele-conferencing (audio,video,
  shared boards) with virtual rooms
• Support for presence of many users (as avatars)
• Introduce a notion of aura to express proximity
  in virtual space
• DIVE uses VRML and MASSIVE uses custom OpenGL
  software

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Proximity and Aura

• An aura is a specification of a region in which
  the service or avatar is visible or present
• When an avatars aura intersect with that of
  another person they can see each other and start
  talking
• When an avatars aura intersect with that of a
  service (e.g. a conference table) the service
  become available
• Depending of the service other users in the
  proximity of the service become visible
  (enabling-amplification)
• Aura concept supports
• Dynamic formation of groups for discussion
• Casual virtual meetings
• Transparent access to services

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DIVE sharing features

• Whiteboard
• Manipulation of 2D graphics
• Live video
• Several users can draw simultaneously
• Documents
• Portable whiteboard that users can bring with
  them
• Single user service
• Can be placed on shared whiteboard
• Conference table
• A service to allow group discussion
• A user join the discussion when his/her aura
  intersect that of the table
• Distribution of documents to participants via the
  table
• Private or active copies of documents
• Podium
• Service to address users withsout the
  intersecting auras
• All users listen to the user at the podium
• Only users with intersecting auras can talk to
  the podium user

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DIVE examples

• Try it
• Logon a department SGI machine (O2 or Octane)
• Start /users/multimed/scubaserver and then
  /users/multimed/scuba (which is the client)
• Visit their site
• http//www.sics.se/dive/

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MASSIVE additional awareness support

• Aura (explained earlier)
• Awareness a meassure of quality of
  service/interaction among objects
• Focus the region that a user pay attention to
• Nimbus the region that a user project itself to
• The level of awareness is dependent on the degree
  of overlap between auras, foci and nimbi
• Relationship between aura and focus/nimbus is not
  clear

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MASSIVE example

• Note there is also a textual interface for
  maintaining an overview of where users are in the
  space

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MASSIVE blackboard
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MASSIVE textual interface
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Some research themes(in the VR community)

• Techniques for visual and haptic presentation
• Display systems
• varying from small mobiles to room size
• Visual field of view
• Application development
• Enhance performance, accuracy and handling of
  virtual environment applications
• Modelling and data acquisition to build virtual
  worlds more easily
• Tracking
• Dynamic interaction
• Shared virtual spaces
• How should a human be presented in virtual space
  (behaviour and expression)

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Application areas

• Engineering visualisation and simulation
• Architecture and design
• Prototyping and design
• Medical training
• Engineering training
• Art and entertainment
• Common information spaces

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Conclusion/Discussion

• DIVE and MASSIVE are still at the kindergarden
  level
• Quality of images is low
• Transmission is slow
• Interface and avatars are not yet sufficiently
  natural
• Many VR environments are still proprietary and
  monolithic
• Prevents integration of common tools and document
  formats
• The don't take documents serious
• Manufaktur is an example of an open
  document-centered CVE
• We need to understand
• The potential application domain characteristics
• When it adds value over more traditional sharing
  of documents and video-conferences
• What is the overhead involved in developing the
  virtual worlds

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Collaborative Virtual Environments - a challenge
to cooperative design?

• The CD discipline has been inhabited with
  computer scientists, designers, psychologist,
  ethnographers, sociologists...
• Now we need to add architects, scenographers,
  dramaturgs, and others with knowledge about rooms
  and peoples behaviour in rooms
• CD has been against the ideas of user
  modelling, but in VE some aspects of user
  behaviour needs to be modelled and simulated by
  the system...
• The computer-based system the VE may be inhabited
  with autonomous agents simulating the behaviour
  of certain typical real world roles
• Expensive equipment - how can we utilize cheap
  mockups?
• 3D projection
• haptic I/O
• Virtual environments are themselves seen as rapid
  prototyping environments...