STEP importer improvements

STEP is the current standard for exchange of CAD data between different software packages. BRL-CAD makes use of the STEPcode libraries to support its step-g converter, but the converter is still in its infancy.

The current importer focuses on AP203 import, and needs to support a large number of data types:

• • Surfaces that are stored individually without Brep superstructure (see, for example, the wing shapes generated by OpenVSP: http://www.openvsp.org/wiki/doku.php?id=step) Even though these are not proper "solids" in the BRL-CAD sense of the term, we can and should import them - if nothing else, we can create one Brep object per surface and then develop post-processing tools to "stitch" the surfaces into a solid.
  • Isolated curves can be brought in as part of sketch primitives.
  • Polygonal data
  • Unorganized triangle mesh data
  • Metadata (in many cases can be mapped to attributes, worst case perhaps store as binary objects...)
  • etc.

Right now our importer is AP203 only - we are also interested in AP203e2, AP214, and AP242.

References

• src/conv/step
  • this is where the current step-g importers and exporters resides
• src/other/step
  • this is STEPcode

• Recommended Practices for AP203
  • http://www.steptools.com/support/stdev_docs/express/ap203/recprac203v8.pdf
• Usage Guide for the STEP PDM Schema V1.2
  • http://www.steptools.com/support/stdev_docs/express/pdm/pdmug_release4_3.pdf

Requirements

• Familiarity with C++