The Domain Message Information Model (D-MIM) is a subset of the HL7 V3 RIM model, and is used to create messages for a particular domain. It includes a fully expanded set of class clones, attributes and relationships. For example, the set of classes used by the Medical Records/Structured Documents domain is quite different from that used by the Patient Administration domain. Thus, the D-MIMs for these two domains will be substantially different even though both will be derived from the RIM.
The D-MIM is a diagram that shows the relationships between the classes using diagramming conventions and notations developed by HL7. These diagrams are based on UML notation, however the HL7 diagramming convention enables diagrams to be smaller and more concise and to convey more information visually.
Just as D-MIMs are a subset of the RIM, R-MIMs (Refined Message Information Models) are a subset of a D-MIM. One of the most popular R-MIMs is for the CDA. The CDA R-MIM is the model used as the basis for defining the CDA document.