The node type must be one of a set of predefined types. The VRML 1.0 standard defines such types as Sphere, Cube, Rotation, PointLight, and WWWAnchor, among others. Fields override the default values of the properties of a node. Each node type defines a set of fields that can be specified explicitly. Fields have names and take values of specific types.
Some node types can have children.
For example, the Separator node can include within its definition the definition of child nodes. Grouping nodes, like Separator, provide a convenient way to associate related nodes. Mini-VRML is a small subset of VRML 1.0, which supports only four nodes. The system we'll be examining in this section serves as an educational exercise and also serves to complement the machinery for drawing the scenes presented in the previous three columns. It provides a subset of the full VRML 1.0 specification.