Hi Mark,
Funnily enough whilst trying to work on a solution for you, I found a little 'hack' workaround for this. Please see the attached video below:
https://drive.google.com/file/d/1YN7I7d ... sp=sharing
As you can see, from the start of the video I start by selecting a beam, then CMD+Option selecting the next fixture gives the next beam an index of 1, then just holding CMD and selecting the next beam gives an index of 2, then CMD+Option to give the next beam the same index of 2, then CMD to give the next beam an index of 3... etc.
This can be quite time consuming with large amounts of beams of course, but at the moment- this is the main way of selecting an index for fixtures. Luckily, I have found a workaround which might help in your case...
If you select each full fixture in order on the left side (1, 2 then 3 as per your image), then you save this as a selection, deselect all and reselect the selection- you can then hold CMD and select the other side of fixtures (1, 2 then 3) and the index will start again from 1- allowing you to select the identical selection as previously with all the index values matching. You can then right click and update the selection to save this, or store it as new.
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Finally- part way though writing I had another thought that would also work for you. If you select all off the beams in mirror order (1 left, 2 left, 3left, 3 right, 2 right, 1 right - with all index's in mirror order also)- you can then activate 'vertical symmetry' within the knight rider effect. See video below for more on that process!
https://drive.google.com/file/d/1_9d9Zv ... sp=sharing
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Hopefully this helps, apologies for the word count!
Kind regards,
Will