Don Brutzman

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VRML and large-scale networking
VRML Consortium Summit 7-8 NOV 97

• Don Brutzman
• Naval Postgraduate School
• brutzman_at_nps.navy.mil

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Presentation overview

• This is my trimmed-down presentation on VRML
  Java Networking
• New points relevant to our summit are highlighted
  in green throughout
• Summary conclusions
• dont fix VRML 97, it works
• large-scale virtual environments now possible
• network research/experimentation in progress

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VRML Overview 2

• Large-scale internetworked 3D worlds are now
  possible
• Scaling up is both technical challenge and
  people challenge
• VRML is what weve been waiting for!
• Stable and compliant browsers are still biggest
  need - BUT recent release of CosmoPlayer 2
  appears to fix that. Thank you, thank you, thank
  you!

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VRML Overview 3

• Dynamic 3D scene description language with
  behaviors and animation
• Rich set of graphics primitives gives
  common-denominator file format
• Well documented, ISO standard
• 20 year history of fracture and incompatibility
  in 3D graphics means we have every reason to
  fail.
• We can continue to defy those odds.

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VRML Overview 4

• Web-capable similar to HTML authors can
  insert/add objects to scene (Inline node) or
  replace entire scene (Anchor node)
• Interpolator animation and interaction
• Script nodes for Java and JavaScript
• Any kind of animation is possible
• First law of engineering if it aint broke,
  dont fix it

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VRML Overview 5

• Open technology, developed by working group,
  ISO standardization
• VRML Repository OUT OF DATE
• http//www.sdsc.edu/vrml
• VRML Consortium page SUCKS (long after a great
  setup by Rikk Carey) http//www.vrml.org how
  about volunteers for web page?
• Working groups losing juice?

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Java

• Numerous desirable attributes for the LSVE
  application domain
• cross-platform, portable code
• recompilation not required
• network support
• VRML compatibility
• minor problems exist, can work around
• serious programming, examples help

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Integrating Java VRML 1

• Class libraries specified for Java-VRML
  interface
• Script nodes encapsulate Java objects embeddable
  in the VRML scene
• ROUTEs link Java object fields/eventIns/eventOu
  ts to 3D node fields
• it works

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Integrating Java VRML 2

• Java objects can query (and interact with)
  browser as well as Web
• createVRMLFromString method enables Java
  objects to generate arbitrary VRML geometry
• a good fit

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Integrating Java VRML 3

• See Annex C of VRML Specification for Java
  Script Authoring Interface (JSAI)
• External Authoring Interface (EAI) is draft work
  in progress which provides alternate
  Java-VRML-browser methodology
• Cosmo Player still has me so pissed off

• now has me so happy!!

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General entity solution
VRML
rendering computation data sharing
Java
network
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Four key network components for LSVEs
rationale for vrtp

• Light-weight interactions
• Short state/event messages via multicast
• Network pointers
• URLs to information resources
• Heavy-weight objects
• reliable client-server response
• Real-time streams - audio, video etc.

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IEEE standard DIS protocol

• Large-scale multicast applications Web
• Truly many-many communications
• Single entity bandwidth ranges from 230..15,000
  bps (bits per second)
• Latency jitter compensated by timestamps
  dead reckoning
• Example behavior/interaction protocol

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DIS-Java-VRML

• Networking is the key hardware bottleneck, not 3D
  graphics rendering
• We think we can create virtual worlds
• open standards
• portable and scalable
• physics-based
• easy as building a web page

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Java used for DIS library

• Can be used to animate VRML scenes via Script
  nodes
• Multicast capable (using JDK 1.1)
• Available Netscape, Internet Explorer
• Portability across platforms enables scaling up
  to many users
• Initial performance is adequate
• (just-in-time Java gets 80 C speed)

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DIS-Java-VRML Data Flow
intended message its pretty simple
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Goals DIS-Java-VRML WG

• Complete freely available Java/C
  implementations of DIS protocol
• Easily stolen examples
• Produce recommended practices for mapping
  between DIS VRML
• Utilities record/playback, viewers etc.
• Math libraries and physics libraries

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DIS-Java-VRML WG admin

• following the usual keys to success
• (which not all working groups have done)
• Open membership
• www.stl.nps.navy.mil/dis-java-vrml
• Meeting 21 November
• Archived mail list
• VRML Consortium
• www.vrml.org

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DIS Testing

• Build testbed lab at NPS
• 5-10 Linux boxes, masters student
• Round-the-clock exercises
• statistics, toolset development
• Low bandwidth going global on MBone
• Emphasis on end-user results
• Other sites welcome to collaborate
• slowww but steady progress

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Test results crucial

• Determine pertinent parameters and corresponding
  values/distributions
• Large-Scale Multicast Applications (LSMA) IETF
  working group requirements
• IRTF Reliable Multicast RG
• Walk-before-run exercise complexity
• Build awareness what LSMAs look like

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Internet-wide VRML animation
Putting physically realistic entities (meaning
real physics, Fma) all interacting together
on a live 3D Web
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Dial-a-behavior protocol

• We are building a DIS-like data protocol,
  modifiable on-the-fly, that will allow rapid
  development of network communications tuned for
  applications
• large-scale multicast
• Public domain software written in Java
• Virtual Reality Modeling Language (VRML)
  compatible and scalable

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Why dial-a-behavior protocol

• DIS entity state protocols hard to modify due to
  hard-coding, slow standards process
• Entity interaction protocols are a crucial
  network capability that need better testing
• Formal grammars and agents can provide a rapid
  modify/test/revise methodology
• Support testing and experimental results!

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protocol-redefinition architecture driven by
application needs
Protocol Definition Interface
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large-scale virtual environments

• LSVEs are now possible
• interactive 3D graphics using VRML
• fully internetworked (need a vrtp)
• extendible in every direction
• scales with the World Wide Web
• that means as easy as building a home page
• details details http//www.stl.nps.navy.mil/brut
  zman/vrml/breakthroughs.html

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multicast networking crucial

• many-many communications, blah blah
• still pretty complicated, slowly improving
• filter packets at network interface card
• Global MBone works, also built in IPv6
• partition network traffic (Macedonia)
• spatial, temporal, functional, your choice
• exploiting reality to better use network
• experimentation testing are essential

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use client/server or peer-peer?

• troublesome cul de sac many conversations
  always seem to end up here
• must we choose only one?
• client/server browsers, http, object request
• peer-peer DIS PDU, other MBone streams
• realization networking is not bipolar, rather a
  spectrum of functionality. Use all of it well.

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why not use the full spectrum?
peer peer
client server
audio video DIS behaviors
http web browser multi-user worlds
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examples in midspectrum
peer peer
client server
audio video DIS behaviors
http web browser multi-user worlds
group-cached http servers (NCSA)
reliable multicast
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what does desktop look like?

• client
• looking at someone elses world
• server
• showing others your world
• peer
• scalable many-many behavior interactions
• everything just works

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what else is on desktop?

• client
• looking at someone elses world
• server
• showing others your world
• peer
• scalable many-many behavior interactions
• everything just works means that network
  monitor capabilities are needed nobody! does
  this yet (even net gods)

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so where does virtual reality transfer protocol
(vrtp) live?
HTML
http
vrtp
VRML 2.0
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vrtp IS NOT...

• possible using just http
• yet another transport protocol
• a competitor to existing protocols
• a step in an untested direction
• about adding complexity
• hard for users to understand
• a push to change VRML, just support it

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vrtp IS...

• a framework for combining essential best-of-breed
  protocols
• a combination of existing software
• a way to give user scenes easy access to a full
  spectrum of network capabilities
• URL extensions client/server/multicast
• easy to use
• all about simplification streamlining
• intended to best support networked VRML

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VRML Symposia in Monterey
sponsored by ACM SIGGRAPH and SIGCOMM in
cooperation with VRMLC
VRML 97 Symposium 500 attendees
(sellout) www.sdsc.edu/vrml97 VRML 98
Symposium February 16-19 Mon-Thurs breakeven 400,
cap 900 ece.uwaterloo.ca/vrml98
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VRML 98 February 16-19 Monterey

• Monday Tuesday
• Tutorials and working groups
• SGI Cosmo dinner at Aquarium
• Wednesday Thursday
• 17 papers (44 submissions)
• 4 panels, to be determined
• Exhibitor booths (not World Movers...)
• Design show, Demo SIG
• Sponsorships available
• Add a day for VRMLC web designers??

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Contact

• Don Brutzman
• brutzman_at_nps.navy.mil
• http//www.stl.nps.navy.mil/brutzman
• Code UW/Br, Naval Postgraduate School
• Monterey California 93943-5000 USA
• 408.656.2149 voice
• 408.656.3679 fax