The VRML server is used for web-based visualization. The server itself is a stand alone
executable with only a commandline interface. However, it reuses the Application
and VisGen components from the other two tools. This made the development of
the VRML server almost trivial. The code only has to parse the commandline, instantiate
the correct objects, and call the appropriate methods.
The VRML server is run over the web from a Java Applet interface. Using this interface, the user selects datasets and the appropriate visualization parameters. The user then chooses to generate VRML. This causes the VRML server executable to be run on the server side as a CGI (Common Gateway Interface) program using the parameters selected from the applet interface. The VRML server generates the VRML and stores it in a file on the server side. It then notifies the user that the VRML has been generated and how large the file is. If the user deems that the size of the resulting visualization is acceptable, the user can click on a button and transfer the contents of the VRML file to the user's web browser (the client). Upon downloading the VRML, the web browser will start up the appropriate VRML plugin or helper application and display the geometry that was generated. This process allows the user to avoid downloading VRML files that are either too small (uninteresting) or files that are too large for the client side web browser to handle.
Figure 7.3: Snapshot from the VRML Server Java Applet Interface