Virtual Reality at Boston UniversityGlenn BresnahanBoston UniversityScientific Computing and Visualization

(http://scv.bu.edu/DAFFIE/BVRG-Talk-Mar02)

AgendaIntroduction to Access GridOverview of DAFFIE systemBridging between VR and AGTiled display wallsDemonstrations

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Access Grid OverviewSuite of commodity hardware and softwareOpen source, Open protocolMulticastTiled projection wallApproximately 90 installations world-wide (7 countries)

FOR MORE INFO...http://www-fp.mcs.anl.gov/fl/accessgrid/http://scv.bu.edu/accessgrid

Distributed VRMulti-person, multi-site shared virtual spaceNavigationAvatar representationTelephony

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DAFFIE OverviewDistributed Applications Framework For Immersive EnvironmentsComponent layersMessaging systemVR protocolClient applications (agents)FOR MORE INFO...http://scv.bu.edu/DAFFIE

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DAFFIE Application ClientsViewerSound serverTelephony generatorSound playerBehavior agentsAudio/video generators/processorsObject generators/manipulators

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DAFFIE Environmentviewerbehavioragentsoundplayerviewertelephonytelephonysoundplayerbehavioragentbehavioragentevent server

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DAFFIE ViewerSGI Performer based Mono or stereo display Workstation, CAVE/Immersadesk, HMD Six-degree of freedom head-tracking Six-degree of freedom navigation Texture-mapped streaming video

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DAFFIE ViewerSimple "script-based" world descriptionGeometric modelsAnimationSoundsMany 3D model formatsInteraction by picking and/or proximityLocal control of time-sensitive animation and soundGlobal update of avatar motion and object state

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DAFFIE Sound ServerTelephony generatorDigitize microphone input Broadcasts "packetized" audio stream Echo suppression

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DAFFIE Sound ServerSound player inputMultiple sound sourcesReal-time audio streams (e.g. telephony)Prerecorded object sound filesAudio attachment objects (3D location)Avatar position in virtual spaceListener position in physical spaceSound player outputMulti-channel localized audio signals

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DAFFIE AgentsControl object behaviorProximity triggersPortalsDevice interfacesKinematic sculpturesVideo sourcing (camera)Audio and video processing

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DAFFIE ProtocolObjectiveState consistencyPersistenceEquipotent clientsNetwork visible stateMessage (event) basedMessage classesDelivery service classesGlobally sequenced, reliable deliveryMessage class subscription

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DAFFIE ProtocolCompound objectsGeometryTransformationAudio hookVideo texture mapComponent ownership/object lockingRequest ownershipBroadcast changesRelease ownershipOwnership transfer

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DAFFIE Messaging SystemMessage router (event server)Multiple delivery service classesGlobally sequenced, reliable deliveryClient application library (API)Point-to-point and broadcastPolled or callback (active messages)Subscription based receiveMultithreaded, non-blockingServicesRegistration, timing, synchronization, query

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DAFFIE Messaging SystemProxy routersFan-in/fan-outTunnelingDirect routing for P2P

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DAFFIE Message routingclientevent serverclientclientproxyclientproxyclientclientclientclientclient

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VR/AG BridgingInterconnect VR and AG spacesVR image display over AGBridge audio in both directionsProvide interactivity for AG participantsAG navigationAG interaction toolsCouple external a/v to both AG and VR

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VR/AG BridgingBostonCyberartsFestival

SC GlobalFOR MORE INFO...http://scv.bu.edu/hipart/GoGrid/

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VR/AG BridgingviewrendereraudiorendererAG nodenavigationvideobridgeDAFFIEMulticastviewerAGaudioAG node

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Tiled Display WallBenefitsLow costScalableMulti-usePassive stereoConstructionLinux cluster display driverInexpensive LCD projectorsCheap polarizing filters

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Tiled Display WallOne or two Linux boxes per projector (plus control node)Two projectors per tileLinear polarizing filtersPolarization-preserving projection screenCustom fabricated projector mounts6 DoF adjusters

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Tiled Display WallPrototype configuration2x2 stereo array (8 projectors)4 Linux display nodes + one control nodeFast Ethernet interconnect

Final configuration4x3 stereo array (2 x 9.4 Mpixel)24 Linux display nodes + one control node52 Linux compute nodesMyrinet interconnect

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Tiled Display WallSoftwareWireGL/ChromiumVTKPerformer + local synchronizationMovie player (several)AlignmentCustom projector mountsComputerized motor controlImaging transformation warpsAutocalibration

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Tiled Display WallIssuesSoftwareAlignmentCustom projector mountsComputerized motor controlImaging transformation warpsAutocalibrationEdge blendingOpto-mechanicalSoftware

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DemonstrationsVR BridgingImmersaDeskDisplay Wall

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