These GitHub repositories contain open source projects and demonstrations that do interesting things with STEP, STEP-NC, and IFC information. Most of them use the ST-Developer libraries or the STEP-NC Machine DLL, which have downloadable versions that are free for personal use.
ST-Developer Personal Edition
- Download - http://www.steptools.com/products/stdev/personal.html
- API Docs - http://www.steptools.com/support/stdev_docs/
STEP-NC Machine (which contains the STEP-NC DLL)
- Download - http://www.steptools.com/products/stepncmachine/download/
- API Docs - http://www.steptools.com/support/stepnc_docs/stepncdll/
You can find more informat ion at http://steptools.github.io/