How can I reorder and orient lines like this?

[Joseph_Oster]

@TheCyclist

I understand how to do it now after looking at your solution using the Set components

When working with sets (or Sort Points), it often pays to round values to a few decimal places (1, 2 or 3) so they aren’t affected by tiny differences. That’s why I added the expression to the pDecon ‘X’ output. I found that pattern in the purple group on the old forum and documented it here:

Set Member Index Example (MIndex)

I don’t think much about how it works anymore but have adapted it many times for similar issues. Just keep a copy of this file handy and copy/paste when needed: MIndex_2017Jan22a.gh (16.5 KB)

Another example:

Separate Lists by Z Coordinate when number per sublist varies

This model (white group) separates your points into branches by their Z values. The cyan group then sorts each branch by their Y values. The purple group is a general purpose ‘Tree/List Viewer’ tool for examining geometry by data tree branch (‘path idx’ slider) and item (‘list idx’ slider). [MIndex_2020May08a] MIndex_2020May08a.gh (19.6 KB) The points are internalized, no need for the Rhino file.

And another:

Homogeneity of a list of points based on position

At first, I did a version of this exclusively for the balcony seats, using their Z values to separate one row from another before sorting by their Y value… Then the light bulb went on - I could do this for all rows!! (white group) MIndex to the rescue (link), except for one very bad point that had a spurious Z value, repaired in the yellow group. [SeatsNumbering_2020Aug28d] SeatsNumbering_2020Aug28d.gh (25.9 KB) [SeatsNumbering_2020Aug28d2] To be a little more robust, I added a “round(x,1…