Onyx is a Structural Equation Modeling (SEM) Graphical User Interface.
It is designed to allow users to build and fit SEMs intuitively and fast, to ease the introduction of Structural Equation Models for beginners, and simplify the transition to more complex SEM scripting languages.
Onyx is developed in cooperation of the Mathematical Psychology Lab at UVa and the Formal Methods Project at the Max Planck Institute for Human Development.
Onyx provides import from and export to OpenMx.
Also, publication-quality figures can be exported in a vector representation to LaTeX or in a JPEG image file. Furthermore, Onyx provides a powerful backend for performing maximum likelihood estimation.
Onyx is intended to be a teaching tool for SEM. It facilitates a graphical approach to modeling that also offers an interface to OpenMx and Mplus code. That is, SEMs can be taught in a graphical approach without the need to
teach a specific modeling language. In the progress of a course, a transition from the purely graphical approach to a specific modeling language can be made using exports to OpenMx or to MPlus. An interactive code view allows users to track and compare changes to the model specification in the selected language that are elicited by changes to the graphical representation.
You can download Onyx for free at http://onyx.brandmaier.de.
You can find a brief user guide at http://onyx.brandmaier.de/userguide.pdf.