As Seinfeld would say “WhaAat’s the deal” ?
Sorting my breps using their center, I am able to sort them in the “Z” direction with “Sort Points” , but in the “X” direction, it’s partly bad.
I checked that my Z values were really equal.
OK, silly rounding issue for the Z values.
The variations are so small that you can’t even see them despite pushing display precision to the max !
Round is indeed the solution. For a more general case with different amount of Breps per “floor”, this would work to avoid Partition List :
230314_PROG_Sort points bug.gh (601.0 KB)
Rounding is often the key to using Sort Points but I can’t see any error at all?
Further examination shows that there is already a logical order to your breps.
Hi Joseph !
I suppose that the issue is tolerance-related.
Nice little cluster for the colors ! Thanks.
The real issue is loosing track of the logical sequence of breps. 
As noted in the cluster properties:
Derived from ‘Colourful’ (by HS Kim?), 12/18/2020
There are four variants:
