This tag defines a collection of class styles (see class3d). All practical uses of this tag require it to use the id attribute for identification within the scene. References to this style are made by id. The style definitions are applied at parse time. Run-time modifications are allowed; however, they are processed as a request to reparse the affected attributes. This is not fast. It is not recommended to animate properties using styles and classes.

The id attribute identifies the name of the style. Individual tags may use the class3d attribute to provide references to named styles. The style attribute values are applied in the order of the specified style names with the last one in the list superseding prior definitions.