140 likes | 223 Views
WHIM S2008. Web-Enhanced Information Virtualization. An Overview of Web-Based 3D Computer Graphics Standards. Why do we need it. Encapsulate computing resources from the user Provide a simplified interface to enhance usability. 2D vs. 3D. Decade-long debate
E N D
WHIM S2008 Web-EnhancedInformation Virtualization An Overview of Web-Based 3D Computer Graphics Standards
Why do we need it • Encapsulate computing resources from the user • Provide a simplified interface to enhance usability
2D vs. 3D • Decade-long debate 2D: Takes less power to compute, easier to encode and transmit; But generally less expressive and compelling, viewer perspective limited by the dimension to the creators’ own 3D: More difficult to model; But easier to manipulate from multiple perspectives and animate more realistic motions.
Standard Artifact: VRML • Virtual Reality Modeling Language, originally named as “VR Markup Language” • A standard for presenting 3D interactive vector graphics • Designed for WWW context
Format of VRML • Uses text to describe vertices and edges of 3D polygons, along with the texture information (mapping, surface color, shininess, etc). • URL can be associated with any graphical component • Aspects of the virtual world (lighting, sounds, etc) can be included in the world file (.wrl) to interact with the user or external events • Support embedded Java or JavaScript code for event-handling.
Code Segment of a VRML file #VRML V2.0 utf8 WorldInfo { title “Just a sample“ info [“ for Apr.29 WHIM presentation"“ks2555@columbia.com"] } Transform { translation 0 2.25 0 children [ Shape { appearance Appearance { texture ImageTexture { url "me.jpg" } } geometry Sphere { radius 0.75 } } ] }
History of VRML Birth: First proposed in a paper submitted to the First International Conference on World Wide Web Popularization: Revamped as VRML 97; established as an ISO standard; became widely used, particularly for education and research area. CyberTown.com’s 3D chat application developped by Blaxxun Software in VRML97 standard
History of VRML Criticism: “VRML was born dead. It never solved any real problems. Good riddance.” --Clay Shirky, on the WWW Artist Consortium mailing list “No integration with HTML, They were too busy getting the 3D to work.” --Chris Phillips, director of business development and multimedia at Microsoft Central idea of these criticism is: VRML gets the job done on 3D part, but its spec is locked, thus there is no easy way to integrate or extend it.
X3D • The successor of VRML, from Web3D Consortium • XML-Based • First approved by ISO in 2004 • Defines several sets of extensions for different purposes • Core set • Interchange • CAD • Geospatial • Immersive • Browser makers can define their own extensions and submit to Web3DC for standardization
X3D’s Improvement over VRML Multiple data encodings New graphics features New networking features Improved APIs, more language/object model bindings Modularity MPEG-4 has streaming interactive 3D using VRML
Interaction Model Add Your Text Text Text Cycle name Text Text Text
Data Encoded in X3D • Sample Java Applet 3D Model Viewer embedded in the html page
Development Enviorment • Xj3D: a Java based developer X3D Toolkit and browser for data modelled in X3D
Conclusion • X3D is a relative junior standard • There are some other competing standards (e.g. COLLADA) alternative to X3D • X3D’s promising for 3D Web Publishing, durability and full potential yet to be seen