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STEP Application Protocols

Application Protocols (APs) are the most visible and widely used parts of ISO 10303. Each AP defines a complete data exchange specification for a specific application domain.

What is an Application Protocol?

An AP specifies:

  • Application context - The domain, life-cycle stages, and intended use

  • Application Reference Model (ARM) - Domain concepts in domain terminology

  • Application Interpreted Model (AIM) - Mapped to STEP integrated resources

  • Mapping table - Formal correspondence between ARM and AIM

  • Conformance requirements - What an implementation must support

  • EXPRESS schema - Machine-readable data specification

Major STEP Application Protocols

Some notable APs include:

  • AP 203 - Configuration controlled 3D designs of mechanical parts

  • AP 209 - Composite and metallic structural analysis

  • AP 210 - Electronic assembly, interconnect and packaging design

  • AP 214 - Core data for automotive mechanical design processes

  • AP 242 - Managed model-based 3D engineering (supersedes AP 203/AP 214)

How APs are Built

APs reuse generic STEP integrated resources (IRs) and application modules (AMs):

  1. The ARM captures what the domain experts need

  2. The AIM maps ARM concepts to existing IRs and AMs

  3. When no suitable IR exists, new resources are proposed

  4. Conformance classes define subsets for specific use cases

AP 210 in Context

AP 210 is the most comprehensive AP for electronic design data. It builds on:

  • Generic product structure and classification resources

  • Shape representation and geometric modeling resources

  • Material property resources

  • Tolerance and datum resources

  • Specialized resources for interconnect and packaging

AP 210 is also a superset of AP 242 for electronic design applications.