@kivahan75 What version of OpticStudio are you using?  In 21.2 (summer of 2021), OpticStudio added the capability of reversing a Black Box:

The “Cannot detector object coordinates” comes from a Ray Aiming failure, so if you’re using OS 21.2 or more recent and you get this error, I would look into the recommendations for Ray Aiming failures (i.e., increase the front aperture of S1, make sure fields are defined in object space, use Robust Ray Aiming, etc).  Also, if you can update to OS 22.1, then you might be able to utilize the new Enhanced Ray Aiming:

https://support.zemax.com/hc/en-us/articles/4415991777299-Introduction-to-Enhanced-Ray-Aiming-and-Ray-Aiming-Wizard

Also, take a look at the LDE after you reverse the system.  Since you cannot have a buried Stop in a blackbox system, the Stop has to be on a dummy surface in the system.  When you reverse the Black Box system, sometimes the Stop is not physically located on the correct surface and you’ll need to manually change this in the LDE itself.

I think I didn't know much about the function of OpticStudio because I just entered optics.
That's right. I have to create a black box after reversing the lens system so that "Cannot detector object coordinates" do not occur.

Thanks for @Alissa Wilczynski , @MichaelH , @Andrey.Pravdivtsev  “