This part of IEC 61360 presents a common ISO/IEC dictionary schema based on the intersection of the scopes of two base standards IEC 61360-1 and ISO 13584-42. The presented EXPRESS model represents a common formal model for the two standards and facilitates a
harmonization of both. The IEC 61360-2 standard forms the master document. ISO 13584-42 contains a copy of the IEC 61360-2 EXPRESS model in an informative annex This standard provides a formal model for data according to the scope as given in the publications cited
above, and thus provides a means for the computer-sensible representation and exchange of such data. The intention is to provide a common information model for the work of IEC TC 3D and ISO TC 184/SC4, thus allowing for the implementation of dictionary systems dealing with data delivered according to either of the standards elaborated by both committees. Two schemas are provided in this part of IEC 61360 defining the two options that may be selected for an implementation. Each of these options is referred to as a conformance class.