This article describes how to associate Multiphysics data to the project they are specified for using Relative to Project file directories or random assignment of ZST file names introduced with version 2025R2.02.
Authored by: Sabrina Niemeyer
Introduction
The Multiphysics Data Loader tool, found in the STAR tab, is used to load FEA/CFD data and assign them to specific optical surfaces. In doing so, the loaded and fitted datasets are copied automatically into the Objects\STOP Files folder as TXT and ZST files. Up to version 2025R2.01 they were named identically to the original file name. When using identical FEA/CFD data filenames for different projects in addition to using the root directory, defined in ‘Folders’ in the OpticStudio Preferences, this may cause issues as the dataset is overwritten. As a consequence, it can occur that data are loaded that are not specifically related to the used project.
OpticStudio provides some functionality to overcome this problem without the need to clean up the STOP files folder for each new dataset or to provide unique FEA/CFD filenames.
Using Relative to Project file directory
The first option is to use Relative to Project directory definitions. With conversion of the project-included loaded FEA/CFD data to a lens file, there is the option available to define the file directories.
In the Lens Project Settings the directory for the files in use can be selected, either linked to the root folder or relative to the project:
The relative to project directory will create an Objects\STOP Files folder next to the Zemax project, containing all selected datasets as TXT and the fitted ZST file. In this way, the datasets are only related to the Zemax project, located next to the Objects folder.
Using random assignment of ZST file names
A new option was introduced in Ansys Zemax OpticStudio version 2025R2.02, which released a new handling for the ZST files. In general, when loading a Multiphysics datafile, a ZST file is generated from it. With the mentioned version, ZST files will have randomly assigned names, and they are only related to the specific Zemax project for which they have been assigned.
Conclusion
This article covers two options to assign Multiphysics datasets to specific projects for which they have been assigned. For versions earlier than 2025R2.02 recommendation is to use the relative to project directory. From version 2025R2.02 as alternative solution the random assignment of ZST file names could be used.
Additional Resources
For more information on project directories, see the article Using Project Directories to organize OpticStudio files.