1. Web-based virtual reality in manufacturing applications
Ramanan S. Tiruvannamalai
08/08/2002

2. Agenda Virtual Reality (VR) VR Types Web-based VR-VRML VRML Case study
Manufacturing applications
Advantages
Limitations
Case study
Conclusions

3. 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)

4. 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)

5. 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

6. Web-based VR VRML – 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)

7. VR manufacturing applications
Virtual prototyping of a sailing yacht
Procedure:
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

8. Virtual prototyping of a sailing yacht
Deck layout of virtual sailing yacht
Interior view of virtual sailing yacht

9. 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

10. 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

11. Simulation of ship production processes
Location of section
Interior structure with top plate removed

12. 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

13. 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

14. 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

15. 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

16. VRML file size – Comparative study
Case study Cont…
VRML file size – Comparative study
S.NO.
Parameters
Simulation time – 50 min
(with step size 0.8sec)
Simulation time – 100 min 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

17. Case study – Boeing VR project
Basic Quest model
With IGRIP workcell

18. Case study – Boeing VR project
With catia parts
With machine kinematics

19. 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

20. References
Anonymous, Web3Dconsortium, VRML, [Online], Available: [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,
Wilson, J. R. (1997). Virtual environments and ergonomics: needs and opportunities, Ergonomics, 40, 10,