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

Agenda Virtual Reality (VR) VR Types Web-based VR-VRML VRML Case study 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 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) www.web3d.org

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

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

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

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.