Locating the point where polylines(3 or more) Intersect

Hello Community,

I have to find the collision(intersecting) point of three transforming poly-lines, or to simplify the problem: locating the collision point of the two moving points (marked as two red points in attached png). I am not sure which way is easier at this point.

Please feel free to open the attached the Gh definition (it needs the reference points in the Rhino file).

If you slide the numeric bar titled "CONTROL" you will see what I mean.

I need the grasshopper to give me the XYZ of that collision point so I can bring it to the next step. Can anyone can help me on this subject?

Thank you very much.

Alex

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Replies to This Discussion

Permalink Reply by Hyungsoo Kim on December 31, 2015 at 1:17am

Hi,

Is this what you want?

Attachments:

LocatetheCollidingPoints_re.gh, 22 KB

Permalink Reply by Alex Jiang on December 31, 2015 at 10:46am

Hello Hyungsoo,

Thanks for the reply, but it's not quite what I want to do.

In your screenshot you numbered the intersection Point with "0,1,2,3", I need the Point where "Point 2" merge with "Point 1".

When you adjust the "Control" slider to around "76.622" (and if you don't change the radius or positions of the circles from points "Pt.Position 1" and "Pt.Position 2"), you will see how "Point 2" and "Point 1" run into each other. I need the XYZ of that meeting point.

Permalink Reply by Alex Jiang on December 31, 2015 at 11:09am

Correction: "Point 3" and "Point 1" run into each other

Permalink Reply by Hyungsoo Kim on December 31, 2015 at 11:47am

Under a given tolerance condition, You can use "cullpt" and find where there are only two points left.
Also you might be able to let GH to find your control degree point(in this case, somewhere 76.622~76.624)by using "Galapagos"(ie; Evolutionary Solver)

Permalink Reply by Hyungsoo Kim on December 31, 2015 at 12:13pm

sorry; wrong item num..

Attachments:

LocatetheCollidingPoints_reV3.gh, 23 KB

Permalink Reply by Alex Jiang on December 31, 2015 at 12:28pm

nice trick with the cull and tolerance, this would work for the moment.

Thanks again

Permalink Reply by Alex Jiang on December 31, 2015 at 12:24pm

Thank you Hyungsoo,

I was looking for something like MCX, but it doesn't quite "record" that magical point yet. Maybe Galapagos gives me the closest approximation but I fear that if I need to do multiple calculations simultaneously, it might be too much for the computer to handle. I will look into Galapagos nevertheless.

Do you think I can have Grasshopper to "bake" a point as 3 polylines meet at the same xyz coordination? Is that something can be solved by scripting?

Permalink Reply by Joseph Oster on December 31, 2015 at 11:24am

Isn't this point just the intersection ('CCX') of these two circles?

Attachments:

LocatetheCollidingPoints_2015Dec31a.gh, 20 KB

Permalink Reply by Alex Jiang on December 31, 2015 at 11:31am

yes, but the edge of the blue fan has to also intersect with these two circles.

in your screenshot, all three points will merge into one at some time when you adjust the "control" slider, and I need that magical point where they all meet.

Permalink Reply by Joseph Oster on December 31, 2015 at 11:39am

68.31140 is pretty close. ;-)

Permalink Reply by Alex Jiang on December 31, 2015 at 11:49am

I know, I see they meet, but just can't get that magical point.

I just think it would be really helpful if we can figure out a way to find the intersecting point between multiple moving geometries, and grasshopper would be able(and I think it's capable) to record these magical moments where they all meet at the same point, and give us the location of that point.

Permalink Reply by Joseph Oster on December 31, 2015 at 12:40pm

The Galapagos way... minimize the length of a polyline connecting the three intersection points:

But it goes on and on and on... and never quite gets there. :(

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