Motion Tracking in After Effects

[David Bogie]

[Dylan Evans] “I seem to be completely stumped on one problem however, I am tracking drumsticks “

Do you mean you’re having trouble tracking the drumsticks or having trouble applying the tracking info to particle layers?

It’s almost impossible to track an object like a drumstick since it is moving faster than your shutter speed can freeze it. Best you can do is track the positions at the peaks of moves when the sticks are slowing down.
It might easier to just place keyframes manually.
or you can track a more discernible object like a ring on the finger of the drummer or his watch and use an offset to move the tracking point out towards the sticks. However, you will need to scale things up a bit to compensate for the distance form the center of the arc.

if you can reshoot it, use a shutter speed of at least 125 or 250.

bogiesan

[Dylan Evans]

Sorry, I dont think im making myself quite clear.

It’s already become apparunt to me that I wont be able to track the drumsticks, its for a music video so eash bit im doing is only a few seconds long. As such I am moving the tracker by hand for each frame.

So the tracking itself is not a problem. however as the tracker only has one point per frame its path is very angular. For example a drumstick my follow an arc from middle bottom, arcing across the left to the middle top, however as it is so fast the only frames thet I have are the bottom frame, somwhere in the middle and the top frame. This means the tracking points are triangular and not the smooth arc the drumstick takes.

You can use the pen tool to smooth the path shown in after effects but this does not change the actual path of the motion, it just jumps from point to point.

[Dylan Evans]

Its never been my nature to just give up, plan B, C etc would be sub par options and I want to try to produce the best outcome here.

It would seem very odd indeed to me if this were not possible.

[David Bogie]

[Dylan Evans] “Sorry, I dont think im making myself quite clear.
You can use the pen tool to smooth the path shown in after effects but this does not change the actual path of the motion, it just jumps from point to point.”

You’re new to this video stuff, aren’t you?
You have a series of images that are only 1/30 second apart. You can only place keyframes at every frame. You cannot draw an arc between the keyframes since they do not travel along an arc, they move instantaneously from one point to the next. Your problem is that you didn’t shoot enough discreet slices of time.

There are lots of things you can do to have fun with this but your insistence that the software is at fault won’t help you create an interesting effect.

bogiesan

[Simon Stutts]

It’s a bit of a stretch…and it might not work…

But you might be able to pull this off by using Motion Sketch to capture your mouse/wacom pen movements to a null object – if you can get them close enough to the movement of the drumsticks, you might be able to pull it off. Wouldn’t be exact, but you might be able to get a similar effect to what you are going for, with a more natural motion.

That said, I dont use Motion Sketch all that often, so I could be wrong.

[Adam Mcewen]

Dylan,

Im assuming you are working at 25 frames per second for this, if not try this but use numbers which apply to you.

So make your comp 99fps (which is the max after effects will allow) in your comp settings then in your time controls change the skip dropdown to 3. This means your comp will still play 25fps but AE will compute three extra frames between each one which plays, this gives you the in between curve i think you are after.

In fact, perhaps a simpler and more flexible work around would be to slow your footage down, animate your movement with your particles set to animate very slow, like you were watching them in slow mo. Render out an uncompressed of just your particles. Import the render back in to AE and speed it back up to fit the footage playing at full speed. This is much more flexible because you can slow your footage as much as you want to give you more in between frames.

Good luck, hope that works out for you.
Adam

[Jim Wilcox]

If you are getting a track that just needs some smoothing you could try applying an expression to your resultant anchor point. The stock Smooth expression right from AE

Smooth(width = .2, samples = 5, t = time)

and adjust width and sample numbers to tweak your outcome…

[Dylan Evans]

That makes complete sence, can’t see that not working, I’ll get back to you with the results, but great idea, thanks.

[Dylan Evans]

Ill give it a go, but i think ive tried somthing simmilar and it doesnt seem to work on a mation tracker path as you might intend.

[Dylan Evans]

Ahh, the typical condecending post, no i’m not new to “all this video stuff” I wouldnt be using after effects if i didnt have a basic knowledge of how frames work.

X amount of particles are emitted each second, they can be emitted in a curve, or a straight line or whatever shape you like, if i have 4 point i can create a cirle with 4 bendy lines.

I never said the software was at fault, the software exists to make these things possible for user. If I want to be able to create it I should be able to, and Adobe gets half my bank account.