Using utility classes significantly reduces the number of lines of code in a Java 3D program. In addition
to the Java 3D core and utility class packages, every Java 3D program uses classes from the java.awt
package and javax.vecmath package. The java.awt package defines the Abstract Windowing
Toolkit (AWT). AWT classes create a window to display the rendering. The javax.vecmath
package defines vector math classes for points, vectors, matrices, and other mathematical objects.
In the rest of the text, the term visual object is used to refer to an ‘object in the scene graph’ (e.g., a cube
or a sphere). The term object is used only to refer to an instance of a class. The term content is used to
refer to visual objects in a scene graph as a whole.