STEP

This page contains the design document for an enhancement or feature. The design should be considered a work in progress and may not represent the final design. As this is a collaborative design, contributions and participation from other developers and users is encouraged. Use the discussion page for providing comments and suggestions.

Converting from STEP files to BRL-CAD databases

BRL-CAD's most pressing need in the geometry file conversion category is support for the STEP file format, a.k.a "STandard for the Exchange of Product model data." Step is a successor to the IGES file format and today is the major standard used for data exchange between CAD systems.

Defining ISO Documents

The source standard for STEP is ISO-10303, which consists of hundreds of individual parts. (list parts important to brlcad)

Existing Open Source Tools

Tools that work with EXPRESS (ISO10303 Part 11) schemas

• Expresso, aka Express Engine, written in Lisp
• JSDAI, written in java

Tools that generate C++ from an EXPRESS schema

• NIST STEP Class Libraries
  • There is a patched version of the SCL that compiles with GCC 4.6
  • Official NIST SCL site

• ESA and NASA also have some tools (expressik, lightcpp, pyexpress) that can generate code from EXPRESS schema. For some years, ESA has planned to release some (or all) of the code as open source; however, they have many higher priorities (per email with a person at ESA).
  • Relevant google searches:
    • iso10303-11 EXPRESS SDAI python generate c++
    • expressik lightcpp
  • IFC contains code generated by lightcpp, but does not include lightcpp. Contains some info on lightcpp.