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Introduction to STEP

STEP (Standard for the Exchange of Product model data), formally known as ISO 10303, provides a comprehensive mechanism for representing and exchanging product data throughout the lifecycle of a product.

What is STEP?

STEP is an international standard that defines how to represent and exchange product data in a computer-interpretable format. It covers geometry, topology, tolerances, material properties, and other engineering data needed to fully describe a product.

Structure of ISO 10303

The standard is organized into numbered parts:

  • Part 1 - Overview and fundamental principles

  • Part 11 - The EXPRESS language reference manual

  • Part 21 - Clear text encoding of the exchange structure (STEP files)

  • Part 200-299 - Application protocols (APs) for specific domains

  • Part 300-399 - Application interpreted constructs (AICs)

  • Part 400-499 - Application modules

  • Part 500-599 - Application interpreted constructs

Why STEP Matters

Manufacturing industries need to exchange and share product information within and between enterprises. Without a standardized method, this is nearly impossible. STEP provides:

  • Computer-interpretable data representation

  • Vendor-neutral data exchange

  • Long-term data archiving

  • Coverage across the entire product lifecycle

STEP File Format (Part 21)

STEP data is typically exchanged using Part 21 files (also called ".stp" or ".step" files). These are text-based files that encode product data according to an application protocol’s information model.

A STEP file consists of a HEADER section and a DATA section, where entities are referenced by numeric identifiers.

Next Steps

In the next lesson, we cover the EXPRESS language that underpins all STEP application protocols.