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Changing amount of movement (Sliders, Nulls, Trackers)
Hi guys,
it’s hard to describe, but let’s try
I have some tracked footage of some guys in front of a greenscreen. The camera is shaking really fast. I used tracking markers on the greenscreen to track the camera movement.
Then I changed the greenscreen into a far distant sky background (you don’t see the floor in the shots).
Now I of course have the problem of parallaxing because the sky background (with some airplane trails and so on) is moving exactly with the tracker and therefore looks like it’s just a wall a few yards away from the actors.So I thought about changing the amount of movement, or lets better say to reduce it so the sky doesn’t move that much with the tracking null. I don’t mean to smooth it out, because the camera movement is harsh and edgy but just to change the amount it’s moving. Let’s say the tracker moves from frame A to frame B with the amount of 100px along the x-axis, then I want to be able to change the amount using a percentual slider to let’s say 50% which would mean the sky only moves 50px from A to B.
With this technique I also would be able to add more layers into the depth and using the percentual slider adjust it so the parallaxing looks good.
I just don’t have the clue how to that…
Is something like this possible?
Would it even make sense or is my approach wrong?Thank you very much!
Dino Muhic – Media Producer
VFX – Motion Graphics – Web-Design – Or just ART
http://www.dinomuhic.com -
2 Replies
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Well, I haven’t actually worked with markers before, but I’m pretty sure you just need the position of the markers to accomplish this.
Come to think of it, I haven’t used a tracker either. 😛 But your basically saying move tracker from point A to point B 100 pixels only along x-axis. You also want a percentage slider. Start by holding the slider’s value with thistemp = effect(“Slider Control”)(“Slider”)/10;
if(temp<=0){0}; if(temp>100){100}If you have a set start and stop time on the timeline, this could work
start = 1;
end = 2;
amount = thisComp.layer(“Null 1”).effect(“percent”).param(“Slider”);
x = linear(time,1,2,value,value+amount);
[x,value[1]]So thats saying as time approaches one sec, hold original value, and as time moves from 1 to 2 sec increase value by percentage null. Hope this helps!
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Thank you but it’s not as simple as that. What I need is a more intelligent script that uses every motion from the tracker and reduces it by the giving percentage of the slider.
The motion tracker (which is basically just a NULL after the mocha part) has keyframes at every frame for position, rotation and scale and all of them have to be used.
Dino Muhic – Media Producer
VFX – Motion Graphics – Web-Design – Or just ART
http://www.dinomuhic.com
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