Hi @overflo!
I think I understand, you run loose led wire around once, such that they all have the same height, then weave another ring through that, also at the same height? Have details on how these are constructed? It’s quite cool!
So if we map each ring on the XY, we can calculate that with some sin/cos based on angle, which we can get from how many LEDs there are on the first circle. Then we repeat for smaller and smaller number of LEDs. Each smaller ring has a different Z coordinate, and also a smaller radius. Is each loop always 2 fewer pixels, with the last (since its odd) being right in the center? Does the transition between rings happen at the same place (looks to be on the left in the video), or do they shift?
When I throw LEDs on my Christmas tree, I hack a spiral or helix map until it roughly matches, and the effect is still decent! Even if we only roughly get it right, it can still look quite good for patterns.
Another way to do it would be to take a photo from underneath with all pixels on slightly, and give it a try with this 2D image based pixel mapper if you know the order by sight. The Z could then be recreated based on the radius from center or pixel index.