What is Onyx?

About Ωnyx

Ωnyx is a free software environment for creating and estimating structural equation models (SEM). It provides a graphical user interface that facilitates an intuitive creation of models, and a powerful back end for performing maximum likelihood estimation of parameters. Path diagrams in Ωnyx can be exported to OpenMx, lavaan, and Mplus to allow an easy transition to script-based SEM software. Also, OpenMx scripts can be transformed into a path diagrams in Ωnyx.

Ωnyx is provided free of charge.

Get a first impression by looking at some screenshots. Read more in the documentation or read our article:

Oertzen, T. v., Brandmaier, A. M., & Tsang, S. (2015). Structural equation modeling with Ωnyx. Structural Equation Modeling22, 148-161. doi:10.1080/10705511.2014.935842


About the team

Ωnyx is a collaboration of

  • Timo von Oertzen
  • Andreas M. Brandmaier
  • Siny Tsang

Special thanks go to:
Joshua N. Pritikin for coding the LaTeX export and the graph auto-layout

Also, we would like to thank:
Ulman Lindenberger, Steven Boker, and the OpenMx team


Our work is supported by University of Virginia and the Max Planck Institute for Human Development.