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 Joseph Oster on January 1, 2016 at 4:53pm

I wrote a general purpose "Domain Search Solver" using Anemone - nested loops that split the original domain by 'Dom Divs' (5..20 suggested) and iterate until a specified precision is reached. Works well!

Also works reliably in another app I have (Hydrostatics) to adjust 'Z-Offset' and re-establish buoyancy equilibrium.

I wasn't able to get it working inside a cluster due to the GH restriction against recursion, unfortunately, because that would be AWESOME!!! Instead, the code is sprawling and exposed...

Note the 'Feedback' input and 'Value' output in the white group (Inner Circle).

Cheers and Happy New Year!

P.S. Geometry internalized, no Rhino file needed.

Attachments:

LocatetheCollidingPoints_2016Jan1c.gh, 41 KB

Permalink Reply by Alex Jiang on January 4, 2016 at 12:24pm

Happy New Year Joseph!

Thank you for all your efforts. It appears that your methods complete something missing from Galapagos. I see that it’s going though loops of calculations, and got closer and closer to the absolute true meeting point, until the buoyancy equilibrium is reached.

However I will have to go with Hyungsoo’s method using Cull Duplicate with a tolerance number set to 0.01: As the three points moving into the tolerated distance, they would merge as one and I will use the coordination of that point for my next task.

This is only to find a structural joint of my kinetic movement device and the tolerance seem to be acceptable, I prefer speed and simplicity at this point.

I will post the animation of the kinetic movement online this week. Thank you for the definition, I’m certain that your theory would be very helpful for my future projects. It is truly a great present for the new year.

Permalink Reply by Joseph Oster on January 4, 2016 at 2:39pm

Glad you like it. I found errors in that code, stay tuned. This subject of quickly locating the zero point value of equilibrium in a given domain, given feedback from geometry, has long been of GREAT INTEREST and value to me.

David Rutten has explained the limitations of searching with an algorithm that is too course or simple, such as missing multiple "near zero" values. That being said, I find plenty of cases where a quick general purpose domain search works FINE to get a useful zero point.

Permalink Reply by Joseph Oster on January 4, 2016 at 6:16pm

Fixed errors that skipped first sub-domain interval?

Note that with 'Dom Divs' set to 7, it takes only 24 tries to get within 0.01 accuracy!

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