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Here we go again: Object following “stroke” in CS6
Hi,
this is a fairly frequent question. There is also a common answer. But is there a better way – in CS6?
The task:
So I want the common draw on effect for a line drawing.
I have a drawing that is revealed through the draw on effect and I want a “green screen hand with a pen” (object) follow the end point of the stroke.The usual procedure:
draw the path on a layer. Copy mask path to the position property of a null object and parent the object (here: hand with pen) to the null. Adjust timing. Solved. Works.The problem:
The drawing is complex and to make it somewhat realistic I have 15 strokes. And while they can be all copied to the position property of the null individually, it is a PITA – much more so, because 15 twisting paths that have to be followed in a total of 3 seconds (I’m going for a timelapse look here) have so many intermediary points, that it is impossible to get them aligned right for the timing to be even close to correct.The solution?
Well, one thing that comes to mind is to follow the usual procedure (painful with 15 paths) and copy the paths all to the position property of the null, one after the other. To avoid losing information of the paths make the stroke effect last for 20 seconds. Get the timing. Pre-Comp. Add it to the final comp and time-remap it. Should work.
But hey! Does it really have to be that way? Is there no goodie in CS6 that will allow me to work with the stroke end point in another way?Greetings,
Johannes -
5 Replies
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Off the top of my head I wonder if tracking might work. Temporarily modify your strokes to draw a line rather than reveal the underlying image. If you’re animating the ‘start’ property, link the ‘end’ property to the start with a small offset (expression pick-whip the other property and add +1 or something).
This should make the stroke effect draw a dot (or very short line) that moves around the path where the writing would happen.
Now track this and use the track for your greenscren hand.
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https://www.jonbagge.net
Jon Bagge – Editor – London, UK
Avid – FCP – After Effects -
Thanks John,
that actually sounds like a clever idea. In my case, since I have a plain white background it should be an easy track. I’ll give it a shot.
Other suggestions welcome 🙂
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Alight,
It seems while in principle it might work for some projects, it does not work for mine. The dots are long lines in my case and even if the tracker would track their movemebt, it would not be able to place the object connected to the null in a meaningful way (i.e. place the pen on the line).
But for other people it might work.
Other ideas, anyone?
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Just a thought, but rather than using an animated stroke to draw your line, perhaps you could use a particle effect instead. By animating a Null along your paths, you’d have a common point to which you could attach your hand object, and which would also serve as the Emitter point for the particles. If the particles are set to have zero motion, they’ll just build up in a line along the path.
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are you using the write-on effct or the stroke effect?
i think using the write-on effect would work best here… simply enable expressions for the brush position and pcikwhip that to the null’s position property.
this way both the hand/pen and the write-on effect will use the same null, thus the timing would be the same….
or am i missing the problem?
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
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