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Intersection of 2 vectors (vanishing point)
Hi I am trying to calculate the vanishing point (E) for some footage I have tracked and applied a 4 corner pin track to. Points a,b,c and d represent the cornerpin points and I am trying to calculate point E by calculating the intersection of vector ab and cd.
——-a
—————-b—————————E
—————-d
——-cCross product?Atan2? I’m not sure how to approach this.
Any help would be greatly appreciated
Pete -
4 Replies
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Unfortunately I don’t have the time to really dig into this, so I’ll just share the first link I found on google with you 🙂
https://www.gotoandplay.it/_articles/2006/08/vectors.php
Hopefully that gives you some ideas?
Darby Edelen
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Hi Darby, I saw that one but I was hoping there might be a javascript implementation around that would be more AE friendly.
Thanks
Pete -
This seems to work as long as a-b or c-d isn’t vertical (you could put in some code to test for that):
a = thisComp.layer(“a”).position;
b = thisComp.layer(“b”).position;
c = thisComp.layer(“c”).position;
d = thisComp.layer(“d”).position;//y = mx + b
m1 = (b[1] – a[1])/(b[0] – a[0]);
m2 = (d[1] – c[1])/(d[0] – c[0]);
b1 = a[1] – m1*a[0];
b2 = c[1] – m2*c[0];
x = (b2 – b1)/(m1 – m2);
y = m1*x + b1;
[x,y]Dan
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Dan Ebberts to the rescue yet again
Thanks so much!
Pete
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