@icybird 

Its not really straightforward, but according to this post:

You can use the API to uncheck the System Explorer..Files..Is Project Directory checkbox. As far as I tested today, the checkbox remains disabled through the user interface and only responds to the API. You can use the following line of code with Python:

TheSystem.TurnOffProjectDirectory()

@Sandrine Auriol said she was going to check why the checkbox wasn’t available through the user interface with the developers.

Take care,

David

@Brian.Catanzaro,

Project directories were introduced with 21.3 according to this article:

https://support.zemax.com/hc/en-us/articles/4407457462803-Using-Project-Directories-to-organize-OpticStudio-files

I imagine that what @icybird is saying is that they have colleagues with earlier versions of OpticStudio that they have to share their files with. And those earlier versions of OpticStudio can’t open ZOS and ZPROJ files. The solution is to use a ZAR, but if the lens file is classified as a project directory (ZPROJ), this is not possible anymore (at least without the ZOS-API trick above). I hope this helps.

Take care,

David

I think ZOS files were also introduced with 21.3 and are likely to be incompatible with older versions of OpticStudio. But at least, ZOS can be saved as ZMX.

Thank you Brian and David for the helpful advice!