Presentation of DIVE, MRToolkit Peer Package, and Paradise

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Presentation of DIVE, MRToolkit Peer Package, and
Paradise Charles Boyd CS 5331 Dr.
Temkin September 7th, 2000
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DIVE
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• DIVE Topics Covered
• Overview of DIVE.
• Why was it created?
• What does it do?
• How does it accomplish its goals? (technical
  aspects)

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Overview of DIVE

• The Swedish Institute of Computer Science
  Distributed Interactive Virtual Environment.
• Currently in Version 3.
• DIVE is covered by licenses, but is freely
  available for non-commercial use.

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Why was DIVE created?

• Primarily to solve problems of collaboration and
  interaction between people.
• To simulate a conference room for long-distance
  shared interaction and information sharing.

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What does DIVE do?

• Creates an internet based multi-user VR system.
• Users navigate 3D space where they see, meet,
  and interact with other users.
• Users interact with each other using virtual
  applications.
• - Virtual white boards.
• - Virtual battle fields.
• - Spatial models of interaction.
• - Virtual Agents.
• - Real-world robot control.
• - Multi-modal interaction.

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How does DIVE work? (technical aspects)

• Operating Systems
• Irix 5.3 and above (SGI).
• HPUX 9.0X and 10.X (HP).
• Solaris 2.4 and above and SunOS 4 (SUN).
• Linux 2.X
• Windows NT (Microsoft)

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How does DIVE work? (technical aspects)

• Networking
• Peer-to-peer approach, no centralized server.
• Communication is handled using SID.
• - A basic communications library.
• - Based on IP multicast and Scalable Reliable
  Multicast (SRM).
• As long as any peer is active within the world,
  the world along with its objects remain alive.
• Since objects are fully replicated on all/other
  nodes, they are independent of any one process
  and can exist independently of the creator.

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How does DIVE work? (technical aspects)

• Visualization (graphics and rendering)
• Behavior of virtual objects are described by
  interpreted Tcl scripts.
• - Evaluated on any node where the object is
  replicated.
• - Scripts are triggered by events in the system
  (ex user interaction signals, timers, and
  collisions).
• DIVE reads and exports VRML along with several
  other 3D formats.

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How does DIVE work? (technical aspects)

• User Interface
• User sees the world through a rendering
  application called a visualizer.
• Visualizer renders a scene from the viewpoint of
  the users eye.
• Visualizer can be set up to use a wide range of
  I/O devices such as an HMD, wands, datagloves,
  etc.

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MR Toolkit Peer Package
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• MR Toolkit PP Topics Covered
• Overview of MR Toolkit PP.
• Why was it created?
• What does it do?
• How does it accomplish its goals? (technical
  aspects)

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Overview of MR Toolkit PP

• Minimal Reality Toolkit Peer Package (MR-TPP).
• Extension of the University of Albertas MR
  Toolkit.
• MR (Minimal Reality) Toolkit is a set of
  software tools for the production of virtual
  reality systems and other forms of
  three-dimensional user interfaces.

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Why was MR-TPP created?

• Because MR Toolkit is a tool which creates stand
  alone virtual reality systems.
• A package was needed to enable a networked
  virtual environment.

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What does MR-TPP do?

• Allows any number of independent applications to
  communicate.
• - Application-dependent data.
• - Device data to remote applications.

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How does MR-TPP work? (technical aspects)

• Operating Systems
• Runs on all major OS for HP, SGI, DEC, PC, and
  IBM RS6000 workstations

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How does MR-TPP work? (technical aspects)

• Networking (protocols)
• Uses UDP packets for network communication.
• Similar to DIS, ignores lost packets.
• Relies on frequent sending of packets, at the
  update rate of the input device, to provide the
  needed redundancy.
• The networked VE operates asynchronously.

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How does MR-TPP work? (technical aspects)

• Software Architecture
• Local copies of shared information are stored in
  a distributed fashion.
• MR-TPP maintains a complete graph topology.
• - Number of packets transmitted is on the order
  of the square of the number or participants.
• - Limits total number of participants to 4 or
  less due to packet loads.

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PARADISE
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• PARADISE Topics Covered
• Overview of PARADISE.
• Why was it created?
• What does it do?
• How does it accomplish its goals? (technical
  aspects)

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Overview of PARADISE

• Performance Architecture for Advanced
  Distributed Interactive Simulation Environments.
• Created at Stanford University in 1993.

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Why was PARADISE created?

• PARADISE was created to specifically address
  network software architecture issues facing
  environments containing thousands of users.
• Contrary to most academic research projects
  which focused on the graphical aspects of net-VE
  design.

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What does PARADISE do?

• Provides a software architecture for large scale
  inter-networked simulation environments.

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How does PARADISE work? (technical aspects)

• Software / Hardware
• Initially ran on a set of four IBM RS/6000
  workstations.
• Used basic OpenGL graphics capabilities.

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How does PARADISE work? (technical aspects)

• Networking and Communication
• Uses a simulated IP multicast protocol.
• Concentration on various update frequencies and
  accuracies for different object types.
• Position History-Based Dead Reckoning (rapid
  changes)
• - Smaller update packets.
• - Better accuracy on fast moving objects.
• Log-Based Receiver-Reliable Multicast (slow
  changes)
• - Focus on reliable multicasting.
• - Eliminated the heartbeat messages found in DIS.

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Important to note

• The most important thing to consider about
  PARADISE is its attempt to reconsider many of the
  standard net-VE assumptions that currently
  existed.
• Work on PARADISE resulted in a series of
  advances in core simulation software technology.

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References

• Singhal, Sandeep. Zyda, Michael. Networked
  Virtual Environments Addison-Wesley, 2000
• www.sics.se/dive
• http//www.cs.ualberta.ca/graphics/MRToolkit.html
  
• http//dsg.stanford.edu/paradise.html