no product structure. AP 203, Configuration controlled 3D designs of mechanical parts and assemblies. AP 204, Mechanical design using boundary representation AP 214, Core data for automotive mechanical design processes AP 242, Managed model based 3D engineering AP 242 was created by merging the following two Application protocols: AP 203, Configuration controlled 3D designs of mechanical parts and assemblies (as used by the Aerospace Industry). AP 214, Core data for automotive mechanical design processes (used by the Automotive Industry). In addition AP 242 edition 1 contains extensions and significant updates for: Geometric dimensioning and tolerancing Kinematics Tessellation Two APs had been modified to be directly based on AP 242, and thus became supersets of it: AP 209, Composite and metallic structural analysis and related design AP 210, Electronic assembly, interconnect and packaging design. This is the most complex and sophisticated STEP AP. AP242 edition 2, published in April 2020, extends edition 1 domain by the description of Electrical Wire Harnesses and introduces an extension of STEP modelisation and implementation methods based on SysML and system engineering with an optimized XML implementation method. This new edition contains also enhancements on 3D Dimensioning and Tolerancing, and Composite Design. New functionalities are also introduced like: curved triangles textures levels of detail (LODs) color on vertex 3D scanner data support persistent IDs on geometry additive manufacturing Structure STEP is divided into many parts, grouped into Environment Parts 1x: Description methods: EXPRESS, EXPRESS-X Parts 2x: Implementation methods: STEP-File, STEP-XML, SDAI Parts 3x: Conformance testing methodology and framework Integrated data models The Integrated Resources (IR), consisting of Parts 4x and 5x: Integrated generic resources Parts 1xx: Integrated application resources PLIB ISO 13584-20 Parts library: Logical model of expressions Parts 5xx: Application Interpreted Constructs (AIC) Parts 1xxx: Application Modules (AM) Top parts Parts 2xx: Application Protocols (AP) Parts 3xx: Abstract Test Suites (ATS) for APs Parts 4xx: Implementation modules for APs In total STEP consists of several hundred parts and every year new parts are added or new revisions of older parts are released. This makes STEP the biggest standard within ISO. Each part has its own scope and introduction. The APs are the top parts. They cover a particular application and industry domain and hence are most relevant for users of STEP. Every AP defines one or several Conformance Classes, suitable for a particular kind of product or data exchange scenario. To provide a better understanding