As a photographer I very often use the same lighting setup in my photo studio as my clients want their portraits or products photos to look the same way no matter when they were shot.
Achieving that is relatively simple, I make notes for every client what lighting modifiers I used, how high my stands were, what effect I used and the distance to the model or product. If I can, I also make a lighting setup diagram, but most of the times a simple Behind The Scenes-photo and the notes will suffice.
If I have the distance from the light stands to the model, I can quickly position the lights right. The same goes for the height. But the angle of the light or the flash is more guesswork, I usually stand where the model would stand and look at the light to see if it feels right.
Together with some shots from the last session with the same client, I can get very near the same results. But it would be even easier if I could just angle the light exactly the same way as before by just using a scale with degree marks. Or just numbers, or something that I can remember.
I don’t think it is very hard to incorporate this little functionality into/onto flash heads, the manufacturers have different designs so they would have to come up with different solutions to having something that can tell the angle.
This would not be very useful if you have your lights on a boom stand, but most of the times my Profoto D1 are on ordinary stands.
Until there is a product for this, I think I will try to make some marks with paint or maybe carve small lines to have something to go after. The quicker I can set up my lights for repeating assignments, the more time I can do other stuff.
If you have any better solution for this problem please let me know.