Virtual Reality and Java 3D - Interactive Web-Based Virtual Reality with Java 3D - page 10

it a better tool for developing more specialized and customized behavior and applica-
tions. This increased flexibility of course is at the expense of steeper learning curve.
Specifically, Java 3D provides more extensive support for behaviors, interpolators,
clipping and collision detection.

• Applicationcomplexity: VRML may be more suitable for simple graphics applica-

tions where the development time is at a premium. When the content or 3D world to
be created is more complicated, Java 3D will be more suitable.

• Fileformat: Being a text based modeling language for dynamic interpretation based

on the source code directly, VRML has a file format that is more standardized. This
is not the case for Java 3D, which has capability to support complied code using low
level API for faster 3D graphics rendering.

• Compatibility: Java 3D is able to support VRML objects through the VRML97

loader. However, it is not possible for VRML to run Java 3D programs.

• Dynamic variation of scene graph: Since Java 3D nodes in the scene graph are

instances of the corresponding classes, the scene graph that describe the virtual 3D
world created under Java 3D can be dynamically changed. This is not possible for
VRML.

• Vendorsupport: There are more vendors that support VRML.

It is worthwhile to note that some parts of Java 3D actually evolve from and is still
dependent on OpenGL. At least in theory, OpenGL can be used for the creation of a 3D
world completely. However, similar to writing assembly codes, it is not well suited for
developing complicated 3D graphics applications due to programming, debugging, and
maintenance efforts. This is a result of the older p roceduralprogrammingmodel adopted
in OpenGL.

mIxed realIty

Mixed reality (MR), which involves the merging of real-world objects and computer gen-
erated graphics to provide the user with additional information and experience, is a more
expansive form of virtual Reality and the continuum of merging between computer-generated
content and the real world. Figure 4 shows the transition from real reality, mixed/augmented
reality to virtual reality (Mark & Livingston, 2005; Wang, 2007).
Example applications include augmenting real objects with computer graphics for
assisting archaeological excavation (Benko, Ishak, & Feiner, 2003), relaying stored ex-
perience (Correia, Alves, Sá, Santiago, & Romero, 2005), teleconference (Bekins et al.,
2006), and virtual human interaction (Egges, Papagiannakis, & Magnenat-Thalmann,
2006). Some application of using MR for educational and training purposes can also be