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3d camera track / tracking person

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Alistair Gallop3d camera track / tracking person
by on Nov 6, 2012 at 3:30:05 pm

Firstly can I just explain what I want to do:
I have footage of someone walking towards the camera -I want to animate a thought bubble above his head that will track his movement and move with him.

I know that motion track will follow his movement but am I right in saying it wont scale the object as he gets closer? From what I can see 3d camera track is supposed to be used to place things on the stationary scene, not the moving objects? So what is the best option to achieve this effect?



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Dave LaRondeRe: 3d camera track / tracking person
by on Nov 6, 2012 at 4:15:11 pm

Why not just scale the thought bubble using keyframes? You could use a 2D track for the vertical & horizontal motion.

Dave LaRonde
Former Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA

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Vishesh AroraRe: 3d camera track / tracking person
by on Nov 6, 2012 at 5:02:32 pm


You can using Motion Tracker in Ae then Check the Scale option in tracker window which will scale the image according to the track.

or try to use Mocha Ae which will give you full control over tracking object with Respective, Rotation, Scale, Shear and Transform.

Go to Animation>Tack Motion

Vishesh Arora
3D and Motion Graphics Artist
Films Rajendra


Demo Reel(3D):

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Alistair GallopRe: 3d camera track / tracking person
by on Nov 6, 2012 at 7:08:40 pm

Thanks guys I will try both suggestions and see how I get on1


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Darby EdelenRe: 3d camera track / tracking person
by on Nov 6, 2012 at 8:51:52 pm

If you have a way to matte out the background you could try a camera track on the subject.

The reason this won't normally work is because the track points in the background will contribute much more to the solve. The subject won't fit into the solution and its tracker points will not be considered. If you remove the background from the equation then AE will attempt to solve with what it has, which is the foreground subject.

Motion is relative, so whether it's the camera moving or the 'world' (world meaning your subject in this case) moving around the camera there's the potential to get a usable track.

This still may not work. It's much less likely to work if the parts of your subject are rotating independently. If, for example, they're walking toward the camera, and they look to the left, then to the right the camera tracker will see different parallax on the face than the body and this may contribute to errors in the solve.

There's a lot that could go wrong, but also the potential to be pleasantly surprised at a usable solve :) Worth a try in my opinion.

Darby Edelen

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