The CRD does not show the significant order of the fields in a section. On the other hand, the CRD shows specializations and other relationships between classes and also some cardinality constraints which can not be made explicit in the file format sections. Specific node sections would be subclasses of class Node, specific edge sections would be subclasses of class Edge and specific Shape sections would be subclasses of classes NodeShape or Line. You can see what node types exist in figure B.2 . Each node has a name, annotation and parent field.
Some node types have additional fields which are given below.
The parent field is not used in the current TCM version but it will be used for hierarchical diagrams. The parent identifier refers to an existing node section. The newly created nodes and edges in that sub-diagram have that node as parent. Furthermore, in sub-diagrams, shapes representing higher level nodes may also occur. In TGD these structures will be almost unconstrained.