Sorting Points from 2 Lists based on their vicinity

I am trying to sort Points from 2 Lists based on their vicinity. I came across an older solution from David, but it is not working in my case. I have tried everything I came across but can not figure it out. I was wondering if someone had a solution for this problem

Attachments:

Point-Sorting.gh, 19 KB

Replies to This Discussion

Permalink Reply by Oliver Hampel on July 20, 2016 at 8:27am

ok I tried some C# code but it seems to have issues as if the IsPointInside is not working right... see attached code

Attachments:

Point-Sorting.gh, 15 KB

Permalink Reply by peter fotiadis on July 20, 2016 at 9:02am

Wait a minute:

Do you want in fact to create some sort of pair prox connections ? (from a given pt in List1 connect to the closest in List2).

Or (alter ego) sample in a DataTree these pairs etc etc.

Used the fastest way ... notify if you want lot's of slower ones (LINQ and the likes).

see attached

Attachments:

PointSorting_question.gh, 14 KB

Permalink Reply by Oliver Hampel on July 20, 2016 at 9:23am

Hi Peter... thanx for looking into my problem - have come across your solutions for others before - Kudos... You are right that I want to pair the points closest to one another. I used your solution and attempted to sort the points based on the lines drawn between them, but they are still not the same... I tried to use the spheres and IsPointInside because what happens if more then 1 line have the same lenght?

Thank you,

Oliver

Attachments:

PointSorting_question_pong1.gh, 17 KB

Permalink Reply by peter fotiadis on July 20, 2016 at 9:32am

Er ...

First things first:

1. If you want to sort the master List1 (or the other) ... well you should FIRST sort the List:

Due to the topology I would strongly suggest some "radial" (so to speak) sort using the "centroid" (ditto) point from List1 as the apex point for the vector angle calculations (with regard some user defined ref Vector and plane).

Notify if you want a Function that does that ... or describe what "sort" means to you.

2 Then do the prox pairs sampling.

Permalink Reply by Oliver Hampel on July 20, 2016 at 9:47am

thanx Peter...

That's why I thought using sphere is the way to go.

with sorting I mean I need the point pairs to have the same index within a list.

I have 176 spheres each containing 2 points. These 2 points are from 2 lists - one from each - the 2 points do not have the same index in their lists.

I take a sphere check against all points from list 1 to see if it is inside. If yes I stick it into a new list1.

I take the same spheres check against all points from list 2 to see if it is inside. If yes I stick in to a new list2.

these 2 list should now have the point pairs having the same index - right???

List<Point3d> sortedPoints = new List<Point3d>();
List<Brep> brepList = new List<Brep>();
foreach (var sphere in spheres)
{
foreach (var point in points)
{
if (sphere.IsPointInside(point, 0, true))
{
sortedPoints.Add(point);
brepList.Add(sphere);
}
}

}

Permalink Reply by peter fotiadis on July 20, 2016 at 9:57am

Well ... don't panic: it's VERY simple:

Leaving sorting List1 aside (Easy: I'll prepare "some" ways ASAP) IF we sample (during the pair matching loop) the current point AND the prox point into a DataTree (with specific order: first the current , then the prox) ... AND THEN split the Tree into 2 ... well the Columbus egg or what?

Of course instead we could sample (during the pair matching loop) the current into a newList1 and the prox into a newList2 and have the very same effect: pairs with THE SAME indices. But a DataTree is more "mysterious" ... therefore preferable, he he (what about having more Lists in mind?: "prox" triads/quads and the likes).

elementary my dear Watson.

But the main point here is not that: it's worth examining various prox finding methods (say for a gazillion of points in List1/List2) and locate the fastest: that's a thingy worth the name I confess.

more soon

Permalink Reply by Oliver Hampel on July 20, 2016 at 10:03am

I concur Sherlock... I was just looking for a down and dirty solution for my problem - which I am trying to solve for 2 days now. I could have just referenced each point by hand - but that would just not be the grasshopper way.... Oliver

Permalink Reply by peter fotiadis on July 20, 2016 at 10:23am

Get the index matching thingy (2 Lists would be more elegant I confess, he he) and allow me a couple of minutes to mastermind 4 of the slowest pair matching methods known to man (in the Name of Science, what else?)

I'll be back, Arnie (Terminator 5)

Attachments:

PointSorting_question2.gh, 138 KB

Permalink Reply by peter fotiadis on July 20, 2016 at 12:09pm

I'm very pleased:

The fastest pair option is ~ 600 times faster than the slowest one (ideal for the Jack Daniels distillery man).

A clear prove that Science is a bad thing.

Of course the connections are so small that nobody can see them ... a fact that makes the whole thingy ultra LOL

Attachments:

PointSorting_question3.gh, 134 KB

Permalink Reply by peter fotiadis on July 21, 2016 at 1:18am

And since progress (kinda) never stops: i.e. more nonsense that supposedly are great (kinda) things ... get the v4 that does LOL and/or ultraLOL stuff as well == progress (kinda).

Radial sort + ultraLOL = true.

No sort + ultraLOL = true.

Roll the bones + ultraLOL = false.:

Moral: LOL

Attachments:

PointSorting_question4.gh, 137 KB

Permalink Reply by peter fotiadis on July 21, 2016 at 2:16am

And since you flirt with the Dark Side (the only side, mind) ... I've added some small challenge for your C# adventures:

modify the first thingy, make 2 squeezed eggs, trim them (or not), populate them with random points ... and then do the sort, the pairing or ... er .... some other more proper stuff (if waves are around to catch).

May The Force (the dark option) be with you

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