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Camera Path + Point of interest
My brain woke me up last night at 5a in reference to this idea… so, I’m turning to Bessy before I begin.
I have a preset path I want to use for the “3d” camera position and another path I want to use for the point of interest position. I know from the podcast (thx Aharon) how to link shtuff to expression sliders, which is what I’d like to do with these position points and paths.
Before I waste time on this personal learning project; Is it possible (y/n) to “slide” the position point from A to B along the path using a key-frame-able expression control? If the answer is yes, I’ll do it. If this seems like something I should have already known, then shoot me because I’ve been key-framing position points for cameras for about a year now. It seems there should be a better way.
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4 Replies
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Yes, it is possible to “slide” a layer along a path using expression controls. Here is some code to get you started:
//–
percentDone = thisComp.layer(“Controls”).effect(“Percent Done”)(“Slider”);
//percentDone represents how far along the motion path the layer is
nullPos = thisComp.layer(“Controls”).transform.position;
//nullPos is the motion path we will follow
currFrame = linear( percentDone, 0, 100, 0, timeToFrames( thisComp.duration ));
nullPos.valueAtTime( framesToTime( currFrame ) )
//–This code would take a layer, and slide it along the motion path of the layer named Controls. As the slider named “Percent Done” on the layer Controls varied form 0-100, the layer would move along the path.
~Colin -
What is the advantage over simply copying the path into position keyframes of the layer?
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I don’t know…
um, I want to be able to do specific arcs, curves, etc. tracks in 3d similar to the film dolly/track setup concept. Having the positions expression controlled gives me the freedom to create the paths before hand in illustrator and import them for specific presets of camera motion; in essence, creating a true virtual set. I might be able to control a null on the “slider path” and parent the camera position to it, I suppose… Any thoughts? I go back to work tomorrow. -
I’d probably link the POI to a null with an expression, and just animate the null. You can get better control that way, because you can see the null even when the camera is not selected.
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Aharon Rabinowitz
aharon(AT)yahoo(DOT)com
http://www.allbetsareoff.com—————————————-
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