Additionally, the Conformance and Minimum Support Requirements section of the VRML Specification is used to specifically minimum conformance requirements of each individual X3D node. This includes basic features that must be supported by an X3D browser. In addition, a node's functionality is further specified with the Field and Event Reference portion of the specification. The Field and Event Reference defines the acceptable format of data fields for nodes. The Concepts portion of the VRML Specification is also used to describe a node's behavior in relation to other nodes and to the world itself.
Semantic requirements are functional descriptions of what defines a node, and how it is defined.
Unlike the more detailed Node Reference, semantic requirements are a series of concise, axiomatic statements to represent any node parameters that may alter the behavior of a node, including other nodes. For each node, a list of semantic requirements exists that define the key functional properties of that node. The test cases will be presented in a list, with each list item containig a description of the test case, and a hypertext link to a X3D world that tests a browser's implementation of the described conformance characteristic. The test world source code containins documentation on what semantic requirement is being tested, a description of the test and expected results, and the name of the author of the test.