Don BrutzmanNaval Postgraduate School

brutzman@nps.navy.mil

VRML and large-scale VRML and large-scale networkingnetworking

VRML Consortium SummitVRML Consortium Summit

7-8 NOV 977-8 NOV 97

Presentation overviewPresentation overview•This is my trimmed-down presentation on “VRML + Java + Networking”

•New points relevant to our summit are highlighted in green throughout

•Summary conclusions•don’t “fix” VRML 97, it works• large-scale virtual environments now possible•network research/experimentation in progress

VRML OverviewVRML Overview 22•Large-scale internetworked 3D worlds are now possible

•Scaling up is both technical challenge and “people” challenge

•VRML is what we’ve 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!

VRML OverviewVRML Overview 33• 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.

VRML OverviewVRML Overview 44• 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 ain’t broke, don’t fix it

VRML OverviewVRML Overview 55• 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•VRML Repository OUT OF DATE•http://www.sdsc.edu/vrml•VRML Consortium page SUCKS (long after a great setup by Rikk Carey) http://www.vrml.org how about volunteers for web page?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?

JavaJava•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

Integrating Java + VRML 1Integrating 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/eventOuts to 3D node fields

• it works

Integrating Java + VRML 2Integrating 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

Integrating Java + VRML 3Integrating 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!! now has me so happy!!

General entity solutionGeneral entity solution

VRMLVRML

JavaJava

renderingrendering

computationcomputation

data sharingdata sharingnetworknetwork

Simple Simple is is

Good!Good!

Four key network Four key network components for LSVEs components for LSVEs rationale for vrtprationale 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.

IEEE standard DIS protocolIEEE 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

DIS-Java-VRMLDIS-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

Java used for DIS libraryJava 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)

DIS-Java-VRML Data FlowDIS-Java-VRML Data Flow

intended message:intended message:

it’s pretty simpleit’s pretty simple

Goals: DIS-Java-VRML WGGoals: 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

DIS-Java-VRML WG adminDIS-Java-VRML WG adminfollowing 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

DIS TestingDIS 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

Test results crucialTest 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

Internet-wide VRML Internet-wide VRML animationanimation

Putting physically realistic entities Putting physically realistic entities

(meaning real physics, F=ma) (meaning real physics, F=ma)

all interacting together onall interacting together on

a live 3D Weba live 3D Web

Dial-a-behavior protocolDial-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

Why dial-a-behavior Why dial-a-behavior protocolprotocol•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!

Protocol Protocol Definition Definition InterfaceInterface

Grammar Grammar parser builds parser builds replacement replacement

protocol protocol managermanager

MultiplayMultiplayer er

networkenetworked d

ApplicatiApplication Data on Data

UnitsUnits

AOIM - Area AOIM - Area of Interest of Interest ManagersManagers

Shared 3D Shared 3D VRML VRML

WorldsWorlds

protocol-redefinition protocol-redefinition architecture driven by architecture driven by application needsapplication needs

large-scale virtual large-scale virtual environmentsenvironments•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/~brutzman/vrml/breakthroughs.html

multicast networking crucialmulticast 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

use client/server or peer-use client/server or peer-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.

why not use the full why not use the full spectrum?spectrum?

client server

peer peer

httpweb browsermulti-user worlds

audiovideo

DIS behaviors

examples in midspectrumclient server

peer peer

httpweb browsermulti-user worlds

audiovideo

DIS behaviors

“reliable” multicast

group-cached http servers

(NCSA)

what does desktop look what does desktop look like?like?

•client• looking at someone else’s world

•server•showing others your world

•peer•scalable many-many behavior interactions

•“everything just works”

what else is on desktop?what else is on desktop?•client

• looking at someone else’s 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)

so where does so where does virtual virtual reality transfer protocol reality transfer protocol (vrtp)(vrtp) live? live?

HTML

VRML 2.0

http

vrtp

vrtp IS NOT...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

vrtp IS...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

VRML Symposia in Monterey

VRML 97 Symposium500 attendees (sellout)www.sdsc.edu/vrml97

VRML 98 SymposiumFebruary 16-19 Mon-Thursbreakeven 400, cap 900ece.uwaterloo.ca/vrml98

sponsored by ACM SIGGRAPH and SIGCOMMin cooperation with VRMLC

VRML 98 February 16-19 VRML 98 February 16-19 MontereyMonterey

•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??

ContactContact

Don Brutzman

brutzman@nps.navy.milhttp://www.stl.nps.navy.mil/~brutzman

Code UW/Br, Naval Postgraduate SchoolMonterey California 93943-5000 USA

408.656.2149 voice408.656.3679 fax