Standard for the Exchange of Product Data (STEP)

A STEP file, which stands for “Standard for the Exchange of Product model data file”, is a standardized neutral CAD file format used to share designs between CAD softwares. The exchange of product data in this file is in accordance with the ISO 10303 standard put together in 1994 and since developed by the ISO committee. It contains all the information about a 3D design and saves it as a series of text documents. Three versions / application protocols (APs) of the STEP standard are used today, each focusing on specific aspects.

🔍 See 3D Data Concepts for details and definitions.

Versions

  • AP203: considers basic geometry, topology, wireframe and surface models, as well as simple assembly structures

  • AP214: adds PMI, color information, layers, geometry relationships (constraints), dimensions and tolerances

  • AP242: adds advanced geometry, color information, topology, PMI, dimensions, tolerances and semantic annotations, kinematic information, explicit deformations, tesselated models and long-term archiving (LTA) formats

All versions are supported by instant3Dhub.

Extensions

Supported:

  • .step & .stp

  • .stpx (XML-coded STEP file)

Not supported:

  • .p21 (identical to .stp & .step)

  • .p28 (XML-coded compressed STEP file)

  • .210

  • .stepz & stpz (compressed STEP file)

  • .stpxz (compressed XML-coded STEP file)

  • .stpnc (Standard for the Exchange of Product Model Data - Numerical Control)

  • .ste

Note that the file extension does not allow for a definitive conclusion about the version.

Structure

Monolithic & nested file structures are supported.

Geometry

Tesselation

A STEP file with tesselated data contains a list of triangulated faces, tesselated edges and vertices and is supported by i3dh.

B-Rep

TBD

PMI & Model Views

TBD

Metadata

Step supports different meta information types. The following is an excerpt:

  • Header: File purpose, file name & file schema

  • Data: Product (part & assembly) information is stored in entities like PRODUCT, PRODUCT_CONTEXT and PRODUCT_DEFINITION.

  • Geometry: Contains unit information and uncertainty tolerances

  • Validation: MEASURE_REPRESENTATION_ITEM contains metadata used for validation

  • Organizational: Entities like APPLICATION_CONTEXT contain information about the context of the application (domain & industry)

  • Presentation: Metadata about styling & presentation (colors, layers)

  • Parts & Assembly: stored in SHAPE_ASPECT and similar entities

Did you find this page useful? Please give it a rating:
★ ★ ★ ★ ★
Thank you for rating this page!
Any issues or feedback?
What kind of problem would you like to report?
Please tell us more about what's wrong: