I'm having trouble sorting a group of randomly ordered points that lie on a circle. I don't care if they're ordered clockwise/counter clockwise or which point is 0 - I just need the point numbers to increase as you walk around the circle (without changing their positions).

I've tried a handful of approaches using some math (dot product, etc), but my main issue is that the sort SOP can't actually access the point number or point position in its expression fields.

Any ideas? Attached is a screen of the points I need to sort

First, create a Circle from the shelf and change the type to “Polygon”. Adjust the divisions to the number of points you want. Then append a Delete SOP and delete primitive 0 (change Pattern from !* to 0) and toggle on “Keep Points”.

You should now have points sorted in a circle.

Hey, thanks for the reply. Unfortunately I need to keep my points exactly where they are - as you can see they are not evenly spaced and that approach would alter the position of my points. Further, since this is part of a procedural system, they may be very unevenly spaced. They will always, however, lie on a circle and I will always have the center point and radius of that circle.

Any other ideas? Thanks again for the reply

Create a circle using the center point and radius that you have, use AttribCreate to make a float point attribute using the expression $PT/($NPT-1), AttributeTransfer this to your points and sort by expression.

If the normal of the plane your points are on is Y (XZ plane), then assuming they are already centered around the origin, you can use this expression in the Sort SOP:

atan2($TZ, $TX)

now that's the elegant solution I was looking for! Thanks Pusat

Thanks to you as well tjeeds! Looks like the atan2 solution will be more efficient

I appreciate the help