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stabilize translation using expression
hello
i’ve tracked an object using mocha pro (only tracked translation nothing else), what i’m trying to accomplish is to keep said object in the middle of the screen, actually it’s the x axis i want to “stabilize”, the y axis is not of concern … (btw. it’s an actor walking from a to b, he doesn’t stay centred all the time)
being a newbie when it comes to ae i don’t know how to apply my tracking data to my videolayer … what expression should i use to keep the y axis in place? and how do i get the stabilization for the x axis done?
thanks for your time
juergen
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6 Replies
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In general, I think you could use something like this:
trackData = motionTracker("Tracker 1")("Track Point 1").attachPoint;
if (trackData.numKeys > 0){
t0 = trackData.key(1).time;
value + trackData.valueAtTime(t0) - trackData
}else
value
You would point variable tackData to your tracking data (I used AE’s tracker). That should keep the tracked point at its initial location.
Dan
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gee … to be honest i don’t understand a word of that code … i simply know nothing about expressions .. i only knew about the possibility to stabilize y axis using expressions cause some ae crack told me so years ago… 🙂
i was hoping someone could walk me through all the necessary steps… might be too much to ask ..
i’ve got my tracking data copied to the clipboard… not knowing where to put it and how to make the necessary changes to it…
i’m sorry to ask that much… i’m just lost…
thx juergen
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I’m not real familiar with Mocha. When you have your data on the clipboard, select your layer in After Effects, and do Edit > Paste, where does the data go?
Dan
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depending on what i’ve tracked (translation/scale+rotation/shear/perspective) it affects anchor point/ position/ scale / rotation … i can paste it on whatever layer i want to… and as i’ve said before .. i’ve only tracked translation ..
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OK, so try pasting the tracking data onto a Null, and apply this expression on the Position property of the layer you want to stabilize:
trackData = thisComp.layer("Null 1").transform.position;
if (trackData.numKeys > 0){
t0 = trackData.key(1).time;
value + trackData.valueAtTime(t0) - trackData
}else
value
Like I said, this isn’t really my area, so maybe someone else will chime in before I make a complete mess of it.
Dan
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🙂 gonna try it first thing tomorrow.. thanks for your efforts .. dan..
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