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Expression to track one end of a line to point and the other remains static
Hey All,
I am building some Motion GFX of an animated diagram overlayed on some moving footage. I have tracked certain parts of the footage I want to highlight. I have a static description pop up and line from that description connects to the moving footage it is describing. So the line that connects it should be tracked to the footage, but still connected to the static description. In essence, one end of the line is frozen and the other end of the line is tracked to an image.
I have been able to come with a process, not elegant, very contrived and not easily repeatable using a Corner Pin and parenting one corner to the tracked data. This has caused a slew of problems since the line comp is not the same dimensions as the Main Comp…the animated end of the line is often some place completely off screen and I have build in an offset, sometimes by eye, and it’s never perfect.
I don’t think this is that hard of an effect, I just can’t wrap my head around an expression to drive it. I think it may have something to do with the scale being linked to the anchor point and stabilizing the position? Am I on the right track? It would be great to make this effect repeatable, I was hoping to just have to link new tracking information for each new line.
Any ideas?
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3 Replies
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Is using the beam effect, and simply pickwhipping the start point to your track, not an option?
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Sorry, I should have been more specific. It’s not a solid line…it’s dotted line created by a line of periods.
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Not behind my computer, but try precomping the dotted line, and using the puppet tool with 2 points, start and end.
You can use simple pickwhips for these positions, that would be the easiest I guess.
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