CVRAT : Collaborative Virtual Reality Authoring Tool KAIST VR Group NVR System

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CVRAT Collaborative Virtual Reality Authoring
ToolKAIST VR Group NVR System

• 97? 8? 21?
• ???

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System Architecture

• User node
• user Input / network processing / simulation
• rendering process
• Services
• group management server
• name server
• geometry model server

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SA Distributed Configuration
Replicated virtual environment
User Node
Name Server
unicast communication
Group Management Server
Multicast communication
unicast communication
User Node
User Node
Persistent CAD model
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Group Management Server

• Session management service
• user join / disjoin ( / failure )
• provide consistent group view
• Virtual environment content service
• name server address
• multicast address

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User Life Cycle
JOIN
DISJOIN
Interaction
VE sync. Group view sync. persistent object
sync. delegate object service
Time sync. Group view sync. VE sync.
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GMS Session management service

• Join
• register new user
• reply current user, multicast address
• time synchronization
• Disjoin
• delegate primary artifact management or store to
  persistent storage in model server
• synchronize group view among members

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SA User Node Architecture v.3
Simulation
Session Manager
UI Agent
Avatar Manager
Coordinator
Human
Replica Manager
Geometry Manager
Renderer
Network Service
Renderer
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Avatar Manager

• Avatar / Ghost Control
• Body / Geometry
• Path / Position
• Gesture / Motion
• Awareness control
• minimize awareness notification message
• temporal, semantical compression
• for
• human perception
• conflict state decision
• replica confidence management

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Coordinator

• Provide the SVE API to Application
• object access
• communication access
• Access Control
• access privilege check
• Concurrency Control
• Spatial concurrency control
• Local (self) / External coordination

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Replica Manager

• Replica Control
• private / shared resource
• Create / Delete replica
• two phase commit protocol
• Update notification
• subset of participants
• Confidence maintenance
• unreliable communication

Partial consistency / perceptual consistency
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Object life cycle
Two phase commit
Two phase commit
create
delete
idel
commit
Local group coordination
Implicit lock
operation
Start update
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Network service

• Multicast communication
• message loss
• Selectively Reliable Communication
• best-effort multicast
• NAK-based RMP NAK-suppression
• ACK-based unicast (subset of group)
• Message ordering
• best-effort, causal, total ordering