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 Resources 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

The file extension does not allow for a definitive conclusion about the version. For example, a .stp file can be AP203, AP214 or AP242. The only way to determine the version is to open the file and check the header information.

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 instant3Dhub.

B-Rep

TBD

PMI & Model Views

TBD

Metadata

STEP includes metadata such as

  • Descriptive metadata: e.g. part names and materials used

  • Structural metadata: e.g. detailing assembly relationships

  • Administrative metadata: e.g. format origin, format version and timestamps

that can generally be accessed by instant3Dhub.

Service Negotiation Key

  • STEP (ASCII): model/step

  • STEP (XML): model/step+xml

  • STEP (compressed): model/step+zip

  • STEP (XML compressed): model/step-xml+zip



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