the formally required AIM/MIM. Today a few APs have ARM based exchange formats standardized outside of ISO TC184/SC4: PLM-Services within the OMG for AP 214 ISO 14649 Data model for computerized numerical controllers for AP 238 PLCS-DEXs within OASIS (organization) for AP 239 There is a bigger overlap between APs because they often need to refer to the same kind of products, product structures, geometry and more. And because APs are developed by different groups of people it was always an issue to ensure interoperability between APs on a higher level. The Application Interpreted Constructs (AIC) solved this problem for common specializations of generic concepts, primarily in the geometric area. To address the problem of harmonizing the ARM models and their mapping to the AIM the STEP modules were introduced. They contain a piece of the ARM, the mapping and a piece of the AIM, called MIM. Modules are built on each other, resulting in an (almost) directed graph with the AP and conformance class modules at the very top. The modular APs are: AP 209, Composite and metallic structural analysis and related design AP 210, Electronic assembly, interconnect and packaging design AP 221, Functional data and schematic representation of process plants AP 236, Furniture product data and project data AP 239, Product life cycle support AP 242, Managed model based 3d engineering The modular editions of AP 209 and 210 are explicit extensions of AP 242. Coverage of STEP Application Protocols (AP) The STEP APs can be roughly grouped into the three main areas design, manufacturing and life cycle support. Design APs: Mechanical: AP 207, Sheet metal die planning and design AP 209, Composite and metallic structural analysis and related design AP 235, Materials information for the design and verification of products AP 236, Furniture product data and project data AP 242, Managed model based 3d engineering Connectivity oriented electric, electronic and piping/ventilation: AP 210, Electronic assembly, interconnect and packaging design. The most complex and sophisticated STEP AP. AP 212, Electrotechnical design and installation. AP 227, Plant spatial configuration Ship: AP 215, Ship arrangement AP 216, Ship moulded forms AP 218, Ship structures Others: AP 225, Building elements using explicit shape representation AP 232, Technical data packaging core information and exchange AP 233, Systems engineering data representation AP 237, Fluid dynamics has been cancelled and the functionality included in AP 209 Manufacturing APs: AP 219, Dimensional inspection information exchange