Dr. David Loffredo
Vice President of Product Development

Dr. David Loffredo is a co-founder of STEP Tools, Inc. and serves as Vice President of Product Development. Dr. Loffredo has been developing engineering software that supports the ISO 10303 STEP standard since 1988. He is editor of the AP-238 integrated STEP-NC model and is also Convener of ISO TC184/SC4 Working Group 11, which develops the STEP implementation methods. He has contributed to the harmonization of STEP GD&T efforts, design of the STEP file exchange format, STEP Data Access Interface (SDAI) functional specification, as well as the SDAI C, C++, and Java programming language bindings.

Principal investigator for the National Simulation Service DARPA Phase I & II SBIR (2010-2016), which built the core of STEP Tools' current digital thread solutions. Also Principal investigator for the Web Smart Modeling Environment Navy Phase II SBIR (2001-2003), which adapted STEP-NC for CNC plate cutting in shipbuilding applications, with special attention to work-sharing between shipyards on the DD(X) next-generation destroyer.

In addition to supervising fifteen major releases of the STEP Tools technology stack, he has developed core libraries for managing STEP CAD design data, as well as libraries for validating and driving CNC controls from STEP-NC machining programs.

He has authored technical papers, articles, and training courses on EXPRESS information modeling, the STEP, STEP-NC, and CIS/2 standards, as well as other topics related to product data exchange and engineering database systems.


Dr. Loffredo received PhD and Master of Science degrees from Rensselaer Polytechnic Institute, as well as Bachelor of Science degrees in both Physics and Computer Science from the State University of New York.

Selected Publications

  • Loffredo, D., “ISO 10303-238: An Integrated Protocol for NC Machining, ” .in Interoperability for Digital Engineering Systems, A. Moreno, Ed, Milan, Italy, FrancoAngeli, 2014, pp. 141-153. ISBN 978-88-917-0600-3.
  • M. Hardwick, D. Loffredo, J. Fritz, M. Hedlind, “Enabling the Crowd Sourcing of Very Large Product Models,” Digital Product and Process Development Systems - IFIP TC 5 International Conference, NEW PROLAMAT 2013, Dresden, Germany, October 10-11, 2013. pp 254-272. doi: 10.1007/978-3-642-41329-2_26, also here
  • M. Hardwick, Y. F. Zhao, F. M. Proctor, A. Nassehi, X. Xu, S. Venkatesh, D. Odendahl, L. Xu, M. Hedlind, M. Lundgren, L. Maggiano, D. Loffredo, J. Fritz, B. Olsson, J. Garrido, A Brail, “A roadmap for STEP-NC-enabled interoperable manufacturing,” The International Journal of Advanced Manufacturing Technology, 2013, doi: 10.1007/s00170-013-4894-0
  • Hardwick, M. and Loffredo, D., “Challenges and Choices in the Specification and Implementation of the STEP-NC AP-238 Standard,” Journal of Computing and Information Science in Engineering, Vol. 7, No. 3, September 2007, doi: 10.1115/1.2768090
  • Hardwick, M. and Loffredo, D., “Lessons Learned Implementing STEP-NC AP-238,” International Journal of Computer Integrated Manufacturing, Vol. 19, No. 6, September 2006, pp. 523-532, doi: 10.1080/09511920600627170
  • Loffredo, D., editor, ISO 10303-238:2007, Industrial Automation Systems and Integration - Product Data Representation and Exchange - Part 238: Application protocol: Application Interpreted Model for Computerized Numerical Controllers, ISO TC184/SC4 WG3 N2101, October 2006.
  • Loffredo, D., editor, ISO 10303-21:2002, Industrial Automation Systems and Integration - Product Data Representation and Exchange - Part 21: Implementation Methods: Clear Text Encoding of the Exchange Structure, Second Edition, ISO/IS TC184/SC4 WG11 N177, October 2001.
  • Hardwick, M. and Loffredo, D., “The STEP International Data Standard Evolves into Manufacturing,” Journal of the Japan Society for Precision Engineering, ISSN 0912-0289, Vol. 67, No. 5, May 2001, pp. 733-738.
  • Loffredo, D., Efficient Database Implementation of EXPRESS Information Models, PhD Thesis, Rensselaer Polytechnic Institute, May 1998.
  • Hardwick, M. and Loffredo, D., “Using EXPRESS to Implement Concurrent Engineering Databases,” Proc. of the Ninth Annual ASME Engineering Database Symposium, Boston, Mass., September 17-21, 1995.