While SGI's Moving Worlds gained the right to be the standard VRML 2.0 specification, the Cosmo Player, a VRML browser from SGI, is still the only one that fully committed to the latest released VRML 2.0 specifications. Many other browsers that support animation and object behaviors still use their own extensions. On the other hand, almost all popular VRML browsers support VRML 1.0 specification. Besides, the nature of building our virtual campus does not demand animations and object behaviors. Thus we choose VRML 1.0 to build our VRML campus.
Many VRML authoring tools have been produced to facilitate the creation of VRML worlds, their abilities to create complex geometric models are very limited. As an industrial standard CAD software, AutoCAD is exceptionally good to create large, complex 3D models. Thus we choose AutoCAD to construct a 3D Texas A&M Main Campus model. The model consists more than 120 buildings, main streets and many side walks around/within the campus. The model is then exported as DXF file format that is later imported into 3D-Studio. A freely available 3D-Studio plug-in VRML converter is used to convert the model into a VRML world. By using the VRML plug-in, one can assign hyperlinks to objects (e.g. buildings) as well as creating lighting effects. The resulted VRML file is under 600 KB in ASCII format without compression. Since this VRML converter does not create the "description" attribute of the WWWAnchor node, neither is it convenient to create custom camera information by using this converter, these information are hand coded into the VRML file. Besides hyperlinks to other Web pages, fifteen objects with links to QuickTime VR single-node movies have been also hand coded into the VRML world. These objects are placed at approximately what the corresponding QTVR nodes have been photographed to give user more realistic looks at those specific locations.
Although our VRML world is optimized and does not require long time to be loaded up into Web browser, it is still desirable for user not to leave the current VRML world when he/she clicks a link to other information. The "target" attribute of the WWWAnchor allows us to present the linked information to a new browser without run into the trouble of repeatedly jumping out/in the VRML world . To assist user navigation in the VRML world, a set of predefined view points has also been hand coded so that users can jump/fly to certain locations. These locations have been chosen as where we shoot our QTVR movies.
The size of our final VRML file is about 630 KB uncompressed, and 87 KB compressed using gzip. The small file size allows fast download through network, even with 14.4 kps modem. Figure 1 shows a screen shot of the world with Netscape's Live3D VRML plug-in.