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Web-based virtual reality in manufacturing applications
Ramanan S. Tiruvannamalai
08/08/2002
Agenda
Virtual Reality (VR) VR Types Web-based VR-VRML VRML
• Manufacturing applications
• Advantages
• Limitations Case study Conclusions
Virtual Reality (VR)
Virtual + Reality
Virtual – “Real in effect although not in fact”
Reality – “can be considered capable of being
considered fact for some purposes”
VR is an oxymoron
Wilson, J. R. (1997)
Virtual reality (VR) Cont..
“Virtual reality is a highly interactive
computer-based environment, where the
user participates in a ‘virtually real’ world
through multiple sensorial channels.”
Mikropoulos, T. A. et al. (1998)
VR types
Broadly categorized into three types Immersive environment
• CAVE system, Head Mounted Display (HMD)
Semi-immersive environment• Large screen projection system with or without
stereo
Non-immersive environment• Monitor based viewing of 3D objects
Web-based VRVRML – Virtual Reality Modeling Language
• Scene description language
• Open and platform independent standard
• Creates Three Dimensional (3D) interactive interface on the Internet
• Scene is composed of list of nodes• Nodes describe things such as shapes, colors,
viewpoints, and transformations
• 3D analog to HTML
• Currently VRML is being replaced by X3D (eXtensible 3D)
www.web3d.org
VR manufacturing applications
Virtual prototyping of a sailing yachtProcedure:
• Provide designers with blueprints and lines plan
• Create 3D CAD models using AutoCAD
• Derive polygonal approximation for the virtual model
• Use texture maps for realistic appearance
• Develop passive virtual model
• Place virtual model on the World Wide Web
Virtual prototyping of a sailing yacht
Interior view of virtual sailing yachtDeck layout of virtual sailing yacht
Advantages – Virtual prototyping
Allows remote customers to inspect the design
details
Improves decision making
Improves negotiation and customer approval
Reduces number of iterations
Reduces time and money
VR Applications Contd..
Simulation of ship production processes
Procedure:
• Design double bottom section for a PD 337
navy cargo ship using AutoCAD
• Simulate the assembly sequence
• Convert into virtual model (VRML)
• Post the virtual model on the Internet
Simulation of ship production processes
Location of section Interior structure with top plate removed
Advantages – Ship Prod. processes
Detects design errors in early stage
Communicates errors effectively over the web to
other departments
Reduces costly time delays
Analyzes clearances and possible collisions
Supports concurrent engineering
Advantages of web-based VR
Improves decision making process
Supports collaborative environment
Improves communication
Supports concurrent engineering
Improves product quality
Supports study of design alternatives
Reduces time and cost
Limitations of web-based VR
Requires powerful computer system with improved graphics hardware
Requires more computational power• For complex models (higher polygon
count)
• Polygon count Vs Rendering speed Requires high capacity networks
• Like Internet2, powerful desktops
Case study – Boeing VR project
VRML created in Quest
Identifies the factors affecting VRML file size
Highlights critical factors
Addresses these limitations to reduce file
size for faster rendering
Case study Cont…VRML file size – Comparative study
S.NO. Parameters
Simulation time – 50 min
(with step size 0.8sec)
Simulation time – 100 min
(with step size 0.8sec)
1 Boeing basic layout + Catia parts + IGRIP workcell + machine kinematics+ labor kinematics
42 MB 45 MB
2 Removing Catia parts from 1
(High polygon count)
20.5 MB 21.5 MB
3 Removing machine kinematics from 2 19.9MB 20.9MB
4 Removing IGRIP workcell from 3 15.4MB 16.2MB
5 Boeing basic layout 8MB 9MB
Case study – Boeing VR project
Basic Quest model With IGRIP workcell
Case study – Boeing VR project
With catia parts With machine kinematics
Conclusions
Web-based VR• Supports collaborative environment
• Improves decision making
• Improves communication
Suitable for SLVR project (NSF) and Boeing VR project
Polygon count of virtual models should be kept as low as possible for higher rendering speed
References
Anonymous, Web3Dconsortium, VRML, [Online], Available: http://www.web3d.org/vrml/vrml.htm [2002, Aug 2].
Beier, K. P.(2000, March). Web-based virtual reality in design and
manufacturing applications. Proceedings of the 1st International Euro
Conference on Computer Applications and Information Technology in
the Maritime Industries, Potsdam, Germany.
Mikropoulos, T. A., Chalkidis, A., Katsikis, A., & Emvalotis, A. (1998).
Students’ attitudes towards educational virtual environments,
Education and Information Technologies, 3, 137-148.
Wilson, J. R. (1997). Virtual environments and ergonomics: needs and
opportunities, Ergonomics, 40, 10, 1057-1077.