AP242

AP242, officially ISO 10303-242, is an Application Protocol within the STEP (Standard for the Exchange of Product model data) framework. It is designed to enable the exchange of model-based definition information and related product data between computer-aided design, manufacturing, and engineering systems.

The standard provides a comprehensive information model for 3D geometry, product and manufacturing information (PMI), and associated metadata. It supports model-based definitions embedded in digital 3D models, including geometric dimensioning and tolerancing (GD&T), annotations, material properties, and other non-geometric attributes. In addition to geometry and PMI, AP242 covers aspects of product structure, lifecycle data, and manufacturing or assembly information, with the aim of enabling downstream processes such as CAM, CAE, and PLM to interpret and use the data consistently.

AP242 is intended to improve interoperability across disciplines and throughout the product lifecycle by offering a standardized representation of design intent and manufacturing constraints. It complements earlier STEP application protocols by focusing on model-based enterprise needs and the integration of 3D CAD data with related information, thereby supporting more integrated workflows and reuse of digital product definitions.

The standard uses EXPRESS-based schemas and can be encoded in STEP-XML or traditional STEP files. It is maintained by ISO/TC 184/SC 4 and is updated through revisions to address evolving industry requirements, particularly in sectors like aerospace, automotive, and machinery where MBDE practices are increasingly adopted.