In brief: As my script loops through all the inputs in my preset (For index = 1 to 40), how can it determine that Input.Find(index) is a virtual input, then identify the "parent PTZ" input, then update itself so that the thumbnail for [index] reflects the current room layout, rather than when virtual input [index] was created or last updated?

Details: Say that Input 1 is a PTZoptics camera, responsible for (or "parent of") virtual inputs 10,14, and 22. And virtual input 10 is a tight shot of the pulpit. When our Nave is reset, we find that, say, the pulpit has been shifted a foot further back, so that virtual input 10 needs to be tweaked. But of course we don't see it in the thumbnail for input 10, since that shows the pulpit in the old position (when we created or updated 10).

If I wanted to update the thumbnails to the current Nave layout, without tweaking the PTZ positions, I could do this manually:
Preview input 10, then Preview the underlying Input 1, then Update 10. And so forth for 14 and 22. Then my thumbnails would be aligned with the current Nave layout.

As a first attempt at scripting (lots of programming experience, none w/Vmix scripting, and very little with vb.net), I'd like to write a script that handles this problem generally. We actually haven 4 PTZ and dozens of virtual inputs, so it'd be a timesaver.)

I've figured out how to loop through inputs. But I'm stuck here:

1. How do I determine that Input 10 is a Virtual Input (rather than an image or a title)?
   
2. If I'm on Input 10, how do I determine that its parent is Input 1?
   
3. How do I script "update 10"?
   

Thanks.

P.S. Further context, in case you're wondering why we could use this: we've gotten a second laptop as a backup, with synching via Google Drive. Works fine, but the thumbnail images don't get copied over (I've not been able to find where they are stored), so when we copy a preset from Laptop 1 to Laptop 2, and then load it into Vmix on Laptop 2, all the thumbnails are gone (=black). This script would save us some time.

Thanks. I'll look into the API XML. I think that answers my first question.

Now how do I determine the parent of a virtual input, and then update the thumbnail?

PTZUpdateVirtualInput - how did I miss that? Thanks.

So something like Input.Find("VirtualInputToBeUpdated").PTZMoveToVirtualInputPosition.PTZUpdateVirtualInput

And I'll check into the Open/Append dialogue, which I've ignored. (I suspect it doesn't show the thumbnail locations, though.)