Hi Brian.  I took a quick look at the local GLASSCAT directory that is created after invoking the new Convert to Project Directory feature:

After opening up a new (empty) lens file, saving it to a specific directory, clicking on Convert to Project Directory, and then selecting the current lens file directory as the place to store local supporting files, I see the default Schott catalog is in the local GLASSCAT folder:

I can then go to the System Explorer → Materials Catalog drop down, and select any of the other glass catalogs that are in the *global* GLASSCAT directory for use in the current file.  For example, here I’ve added the Infrared catalog:

Now if I look at the local GLASSCAT folder, I see that the Infrared catalog has indeed been added, but so have some other *.dat and *.grd files (not sure why that happens...):

In any event, I assume that subsequent changes to the loaded catalogs will remain local to the current model file directory.

Now, however, if I try to add a new local glass catalog file manually by cut-and-pasting, it doesn’t show up as a loaded file in the Materials Catalog drop down menu.  I tried this using the Corning catalog.  But, say I then try to insert a Corning glass into the model, I get the usual prompt:

If I select Yes, the Corning catalog is added to the file, but if I look at the local GLASSCAT folder I see not only the Corning files, but several other catalog files too.

I have no idea why this is happening…  These other glass catalogs are not available for use in the lens file:

So, it looks like there are some idiosyncrasies that need to be ironed out…

This may be an unanticipated workflow.  The use case I am describing is:

• I have a design
• I want to make a copy of the design and add some components that depend on custom glass catalogs
• I copy the design to a new directory
• Now I want to add surfaces that use glasses from custom catalogs that are not stored in the ..\Documents\Zemax\Glasscat folder.

(I’ve already implemented the obvious work-around.  Copy the custom glass catalog to ..\Documents\Zemax\Glasscat folder)

It seems like the use case for Convert to Project Directory is to archive your design.