Virtual Real-time 3D Object Sharingfor Supporting Distance Education and Training

Hiroko SuzukiFaculty of Computer and Information Science,

Hosei University,

n00k1126@k.hosei.ac.jp

Presentation Outline

• Objectives

• System Design Ideas

• Implementations– Communications– Rendering

• Discussions of Implementation Results

• Conclusions

Objectives

• Supporting distance education

• Training of younger/junior designers

System Design Ideas (1)

• What is this application?It allows group participants to share: working space3D objectsmanipulations on the 3D objects in real-time

such as moving, scaling, generating,…

System Design Ideas (2)

• Communication styleServer-Client architecture

• How to avoid the bottleneck network problemReduce the amount of transmission data

whole of 3D object data

action event, object ID, transformation data,…

System Design Ideas (3)

• How to avoid the collision problemAction collision

equal-right policysupervisor or tutor oriented policy

User Interface

B

A

C D

E

Manipulation space Working space

Implementations (1)

• Server functionalityMember Management

RMI Server Functions

Object Management

Database

• Client functionalityUser Interface

Local Data Management

RMI Client Functions

Rendering

Database

Implementations (2)

• Communication toolJava RMI technology

simplify programavoid unnecessary data communicationsmulti-thread communicationcallback function

public class ServerImpl extends UnicastRemoteObject implements ServerInt{ …… public static void main( String[] args ) { System.setSecurityManager( new RMISecurityManager () ); try{ ServerImpl obj = new ServerImpl(); Naming.rebind( "Server", obj ); } catch ( Exception e ) { } } ……}

public class ClientImpl extends UnicastRemoteObject implements ClientInterface { …… public void connection ( int flag ) { switch( flag ){ case 0 : ServerInt server = (ServerInt) Naming.lookup( "rmi://" + addr + :1099/Server"); break; case 1 : server.addMember( user, client ); break; case 2 : server.shareMember( user_name, share, parameters ); break; case 3 : server.addObject( share, user, obj.wfr.pf.par ); break: …… } }}

A fragment code for communications

Implementations (3)

• Rendering toolJava 3D API

simple and high-level programming model adding objects, lighting up, view, adding texture enabling interaction with objects…control the behavior of 3D objects

Discussions of Implementation Results

Transmission time versus the number of objects

Rendering Timeversus the number of objects

Environment: 1 RMI server and 2 client machines on same LAN

Conclusions

• Virtual real-time 3D object sharing enables collaborative group activities effectively

• I will present this paper at the international conference on AINA2004.