STEP Writer

Standard for the Exchange of Product Data (STEP)
File Extension: STEP STP STPZ STEP STP STPZ
Supported Versions AP 203 Ed2 - AP 214 Ed1 - AP 242 Ed1, Ed2, Ed3
Platforms wy ly my an iy
Assembly c_green Supported
B-rep c_green Supported
PMI c_green Supported
Tessellation c_green Supported
Views c_grey_g

STEP (Standard for the Exchange of Product Data) is a widely-used ISO standard file format for representing 3D product data. It is commonly employed in industries such as manufacturing, engineering, and aerospace for exchanging 3D models between different CAD systems. The STEP format supports detailed and accurate representations of 3D objects, including geometry, topology, and product manufacturing information (PMI). This makes it ideal for applications requiring interoperability, data exchange, and long-term archiving of product information.

Our STEP reader provides full access in reading and writing to the assembly, B-rep and PMI.

STEP uses Application Protocols (AP) as versions, which can be seen as specific subsets of the STEP standard.

How to Export to STEP

Our STEP reader supports the following Application Protocols (AP) of the standard:

  • AP 203 Ed2
  • AP 214 Ed1
  • AP 242 Ed1
  • AP 242 Ed2
  • AP 242 Ed3

To export a model file to STEP format, call A3DAsmModelFileExportToStepFile(). The format-specific A3DRWParamsExportStepData is used to describe how to export it.

A3DRWParamsExportStepData sParamsExportData;
A3D_INITIALIZE_DATA(A3DRWParamsExportStepData, sParamsExportData);
// ... set export parameter options

A3DAsmModelFileExportToStepFile(pModelFile, &sParamsExportData, "path/to/file.step");

Compression

The full assembly tree is exported with all the instancing information maintained. Views, camera definitions, sections, and PMI visibility are supported by our STEP file writer.

To export to a compressed STEP file, change the output file extension to “stpz”. Please note that this feature is only available with STEP AP 242 standard.

Tessellation

Our STEP writer supports the export of tessellated geometry to the AP242 format. This includes tessellated solids, shells, wires, and point sets.

HOOPS Exchange only export tessellated data from import files originally containing only tessellation data. As such, to write to tessellated STEP, your originating file needs to have been imported with A3DRWParamsGeneralData.m_eReadGeomTessMode set to kA3DReadTessOnly. Writing B-rep and tessellation together is not yet supported.

If a part contains solids with no B-rep, all of the geometry for this part will be exported as tessellated geometry for the AP242 format. This includes TESSELLATED_SOLID, TESSELLATED_SHELL, TESSELLATED_WIRE, and TESSELLATED_POINT_SET.

B-rep

When we export to STEP we look at the source data and map each surface to one of the following:

  • B_SPLINE_SURFACE
  • B_SPLINE_SURFACE_WITH_KNOTS
  • CONICAL_SURFACE
  • CYLINDRICAL_SURFACE
  • DEGENERATE_TOROIDAL_SURFACE
  • OFFSET_SURFACE
  • RATIONAL_B_SPLINE_SURFACE
  • RECTANGULAR_TRIMMED_SURFACE
  • SPHERICAL_SURFACE
  • SURFACE_OF_REVOLUTION
  • TOROIDAL_SURFACE

Curves are mapped to:

  • B_SPLINE_CURVE
  • B_SPLINE_CURVE_WITH_KNOTS
  • CIRCLE
  • COMPOSITE_CURVE
  • POLYLINE
  • RATIONAL_B_SPLINE_CURVE

PMI

PMI is supported by our STEP file writer. HOOPS Exchange supports export of semantic PMI to the STEP AP242 format.

This includes:

  • ANGULARITY_TOLERANCE
  • CIRCULAR_RUNOUT_TOLERANCE
  • COAXIALITY_TOLERANCE
  • CONCENTRICITY_TOLERANCE
  • CYLINDRICITY_TOLERANCE
  • DATUM_FEATURE
  • DATUM_TARGET
  • DIMENSIONAL_LOCATION
  • DIMENSIONAL_SIZE
  • FLATNESS_TOLERANCE
  • GEOMETRIC_TOLERANCE_WITH_DATUM_REFERENCE
  • GEOMETRIC_TOLERANCE_WITH_DEFINED_AREA_UNIT
  • GEOMETRIC_TOLERANCE_WITH_DEFINED_UNIT
  • GEOMETRIC_TOLERANCE_WITH_MAXIMUM_TOLERANCE
  • GEOMETRIC_TOLERANCE_WITH_MODIFIERS
  • LINE_PROFILE_TOLERANCE
  • MODIFIED_GEOMETRIC_TOLERANCE
  • PARALLELISM_TOLERANCE
  • PERPENDICULARITY_TOLERANCE
  • POSITION_TOLERANCE
  • ROUNDNESS_TOLERANCE
  • STRAIGHTNESS_TOLERANCE
  • SURFACE_PROFILE_TOLERANCE
  • SYMMETRY_TOLERANCE
  • TOTAL_RUNOUT_TOLERANCE
  • UNEQUALLY_DISPOSED_GEOMETRIC_TOLERANCE

It is possible to export PMI representation as polylines (text will be outlined) or tessellated (text will be filled).

Miscellaneous

The following information is also supported for export by our STEP writer:

  • File attributes * Authorization Name. * Organization Name * User Name
  • User-defined attributes on geometry and part (AP242 only)
  • validation properties on geometry, part and PMI (AP242 only)

Limitations

Currently the HOOPS Exchange API does not support export of STEP drawings.