It is reasonably fast, portable, and, like VRML, tightly coupled with the Internet. Let's begin our journey into three dimensions with a look at how a VRML document is structured. The information provided in this section is based on the VRML 1.0 specification. We'll be focusing on the overall structure of a VRML document, but you can find more detailed information in the Resources section of this article. Scene descriptions in VRML are made up of entities called nodes .
Nodes can be shapes, properties, transformations, cameras, and lights.
Nodes can also be clusters of other nodes, as we'll see a bit later. A VRML description consists of a single top-level node. That top-level node may contain other nodes, called children, as illustrated in the diagram below. We can rearrange the figure to indicate containment, with descending line segments between adjacent nodes. This top-down arrangement is illustrated below.