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.