Java 3D Overview - Interactive Web-Based Virtual Reality with Java 3D - page 30

• In a standalone application, the entry function has a name of main as shown in Figure

1(b). However, in an applet, the entry function is its constructor. As an example, the
constructor name is the same as the class name RotatingCube in Figure 1.

• The path of the files stored on the server has different representations. In a standalone

application, a direct absolute or relative file path can be used. On the other hand, in
an applet application, only URL-based path can be used. For example, the picture
file picture1.gif, which is in the same directory as the java 3D code, can be loaded
in Line 1 of Figure 1 in a standalone application. For an applet, the method given in
D.6 of Appendix D has to be used instead.

• A standalone application can run under the Java runtime environment, while an

applet must be embedded in a HTML file, and run under Internet Explorer or other
browser.

In general, it is often easier to develop and test a standalone application first, before
migrating to a Web-based applet for further debugging and evaluation.

summary

In Java 3D, the objects in a virtual 3D world are described in the form of a scene graph.
This is a tree like structure consisting of a hierarchy of nodes containing information on
objects or groups of objects on geometries, shapes, lights, sounds, interactions, and so on.
Specifically, the root of the scene graph is a virtual universe that may have several locale
branches. Also, each locale may hold related objects that are next to one another at a certain
location in the 3D world, and may be made up of many branch and transform groups. Each
branch group is a subgraph of the scene graph, and can be compiled for rendering efficiency.
Also, by setting certain capabilities, branch groups can be attached or removed for interac-
tion with the user during run time. In addition to the content branch, which describes the
visual objects in the virtual world, the scene graph also needs at least a viewing branch
for describing the how the user views the 3D world. The setting up of this branch can be
carried out easily by invoking a simple universe. Alternatively, multiple views of the same
virtual world can be obtained for applications involving multiple displays.

references

Colon, E., Sahli, H., & Baudoin, Y. (2006). CoRoBa, a multi mobile robot control and
simulation framework. International Journal of Advanced Robotic Systems , 3 , 73-78.

Hobona, G., James P., & Fairbairn, D. (2006). Web-based visualization of 3D geospatial
data using Java3D. IEEE Computer Graphics and Applications , 26 , 28-33.