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Is there a way to manually track a point in motion?

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Brad Thomson
Is there a way to manually track a point in motion?
on Dec 2, 2012 at 6:26:41 pm

Hi there,

I'm new to motion 5 and am trying to use tracking to make a few blood hits seem real. In the clip I want my actor to get shot in the chest, and there to be a blood burst on the wall behind her as well. When I try to track the shot and hit analyze it never stays on her chest where I want the blood hit to register. I chose a high contrast point as she is wearing a shirt with a small black heart on it by her right shoulder. However everytime I try to use the point and analyze the clip, the clip doesn't want to follow my point. It definitely strays. I was hoping possibly I could perhaps go frame by frame and manually track the point that I want it to follow myself to take the guess work out of it. Is there a way to do this, or perhaps a way to get a better track? This isn't a tripod steady shot either by the way. It was shot hand held with a little bit of camera motion in time to her shoulder moving back to really sell the blood hit. Any suggestions would be much appreciated! Thanks!


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Jason Watson
Re: Is there a way to manually track a point in motion?
on Dec 3, 2012 at 1:08:48 pm

Brad-

Add the Analyze behavior to your clip as you normally would. Then go to the Track 1 properties and add a keyframe to the Position parameters on the first frame. You can go frame by frame adjusting the position as needed. (Just don't select 'Analyze' to start the analyzing process or else Motion might overwrite what you've already done.)

Alternately, you can let Motion do its analysis first and then go into the keyframe editor and manually adjust every position frame, cleaning up as needed. If the drift is on the whole not acceptable, the other method might be preferable.

One final method that might work for your situation- since you are tracking a heart, if it stays relatively the same shape (that is, you see it the same with only X and Y position changes and little to no rotation, you could recreate that heart by drawing it, overlay it on the footage and perhaps more precisely follow the footage without trying to remember where on the edge you had your contrast point. You could then add use the heart you animated as the source for Match Move. Could be even more tedious, but might give better results.


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Brad Thomson
Re: Is there a way to manually track a point in motion?
on Dec 5, 2012 at 2:40:19 pm

Thanks for the response! I ended up finding the tab that allows me to lower the accuracy of the analysis before it stops which allowed it to at least analyze every frame I needed in the clip, as before it was stopping and giving up before the clip was finished. Then I moved every point manually in every frame. However those other methods are very helpful, and I will have to try that.

My only other question would be is there a way to allow my actor to partially cover part of the clip I'm sticking the tracking point to at some point in the clip? For example I was doing a test on some blood spatter on the wall behind my actor but her shoulder goes in front of part of the blood splatter on the wall for a couple seconds. Is there a way to separate her from the background so that her silhouette covers the blood splatter that's supposed to be on the wall in the background? I know I could use a green screen to start with, but being as the scene is already shot without one is there a way to make it work still? I greatly appreciate the help! Thanks for the response


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Jason Watson
Re: Is there a way to manually track a point in motion?
on Dec 5, 2012 at 3:07:09 pm

If I'm understanding you correctly, the track point you are using gets covered up briefly and you want to see if you can cut the actor out so as not to affect the tracking point?

I'm not sure there's an easy way to get around that, but I'm also not incredibly experienced with tracking. Even if you cut the actor out you'd still lose the tracking point since as far as the pixel information goes, the blood behind her doesn't exist.

You could try clone stamping as best as you can the blood from each frame of the lost tracking point in Photoshop, eventually bringing it in as an image sequence and tracking that. After the analysis is complete you could apply the tracker to the original footage and adjust as needed.

Of course, if the lost tracking is not that long you could try just manually adjusting the tracking point.

Finally, if neither of those options works, you might look for another place in your footage to track. If the wall has even a little bit of contrast (nicks, splotches, etc.,) you could add a Brightness/Contrast and overdo it so you get a point with lots of contrast. Track a point and then apply the analysis and tracking to the original footage.

There might be other, more efficient ways to deal with this that I am unaware of, but I hope that's helpful.


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Brad Thomson
Re: Is there a way to manually track a point in motion?
on Dec 5, 2012 at 5:07:17 pm

Basically in the shot I had a blood hit on her chest which after figuring out how to manually track, it worked quite well. But then I wanted to add some blood splatter on the wall behind her to add to the effect. I placed my tracking point on the wall where I wanted it to hit and it worked well after I manually tracked it again. The actual tracking point doesn't get covered however some of the effect to the left of it gets overlapped by her shoulder. Because the effect is tracked to my base clip it ends up staying over top of her shoulder that moves in the way of it for a couple frames, which kills the idea of the effect being behind her on the wall. I was just wondering if there was a way to mask her somehow and make her shoulder end up over the effect but the effect still over the background.

I didnt explain that too well in the last post, sorry! I'm still just getting my feet wet with visual effects and am trying to get as much info as I can to learn how to make things work in certain situations.


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Jason Watson
Re: Is there a way to manually track a point in motion?
on Dec 5, 2012 at 5:23:25 pm

Ah, now I see. :-)

The most straightforward approach (I think) would be to mask the actor and then place that masked layer on top of the underlying footage layer with blood spatter layer you added in between. Depending on the amount of movement (both from the actor and camera) the masking process could become quite tedious, but it can certainly be done.

If you have After Effects you might try its masking tool since in theory it can extrapolate the mask movement from frame to frame, but it will of course be dependent on the footage itself and how conducive it is to that particular tool.

Update: I just re-read your post and you said that the problem spot is only a couple of frames- if that's the case, masking just the shoulder shouldn't be too difficult. Start with the first frame where this occurs and mask as needed, and then animate the mask frame by frame until you get the result you need. Depending on the footage (how crisp the edges of the shoulder, lighting, etc.) you may or may not want to use a small feather on the mask. Once the masking does what you want, just place that masked footage layer on top of the effect and the original footage. You may have to tweak some things to compose it realistically, (assuming that's what you're going for) but that's pretty much the most basic way to get there.


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Brad Thomson
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 3:49:45 am

Thanks for your reply Jason, I've been trying to do masking in at least the first frame to see if I can get the effect to go behind my actor and in front of the background and I've been failing miserably! lol I stopped it at the first frame where my actor needs to be masked out and then chose the bezier tool to mask around the portion that needed to be masked. Unfortunately this just made a white blotch where my actors head was. If I turn down the opacity of on the bezier layer I can see my actor again however the effect still for some reason ends up on top of my actor even though the bezier layer is above the effect layer in the editor. I have to admit, I'm confused. Looking through all the menus I can find I still can't find a way to make this work. Any advice for an effects noob? Thanks again for your help!


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Mark Spencer
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 3:50:42 am

You are using the shape tool instead of the masking tool.

--
Mark Spencer
Freelance Producer/Editor/Motion Graphics Artist
Apple-certified Master Trainer
Author, Motion 4 from Peachpit Press
http://www.applemotion.net


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Jason Watson
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 4:21:35 am

Mark is correct- it sounds like you were using the shape tool instead of the masking tool. If you want to make a mask directly on the layer, use the Mask Tool- you can even use the Bezier Mask option to be as precise as you need.

However, if you already have a shape created and don't want to redo everything, you can also use that as the mask: on the footage layer you want to mask, simply add a layer mask and then use the shape you drew as the source for that mask. When you do this Motion will default to hiding the source for the mask, so you shouldn't see the white any more. Make sure the opacity is 100%, since the mask is drawing its opacity from that shape.


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Mark Spencer
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 4:23:04 am

Even better - drag that shape onto the copied video layer and wait a beat - you'll get a menu that will allow you to convert the shape into a Mask!

The reverse works as well - if you drew a mask and wanted a shape, just drag the mask to a group.

--
Mark Spencer
Freelance Producer/Editor/Motion Graphics Artist
Apple-certified Master Trainer
Author, Motion 4 from Peachpit Press
http://www.applemotion.net


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Brad Thomson
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 4:43:43 am

As you can tell I'm extremely new to masking. In fact trying it for the first time, I'm sure there's lots of facepalm moments waiting for me as I learn more haha. Thanks for your patience and thanks for the help, it's much appreciated! Finding tutorials for motion in this kind of thing isn't giving me much luck so this helps a ton!

So I switched to the bezier mask tool and masked out the shape of my actor. Now I have a "bezier mask" menu that comes up in the inspector to the left. I can see the whole scene if I select mask blend mode "add", or if I hit mask blend mode "replace" it just gives me the actor on a black background. So now I'm trying to find a way to make my actor on the blank background her own layer but keep the background as well so I can throw the mask above the effect in the layers menu and to my mind I would then theoretically have my shot with my actor in the foreground and my effect stuck to the background. Any suggestions?


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Jason Watson
Re: Is there a way to manually track a point in motion?
on Dec 7, 2012 at 11:51:15 pm

If you have it to the point where the actor is masked with a transparent background, all you'd really need to do is duplicate that layer, (if you don't already have a duplicate) place it below the masked layer and get rid of the mask on the bottom layer. Your blood spatter would then be a layer in between.

You'll probably need to make adjustments to get it looking right, but that's the basic idea.


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Arlo Rosetta
Re: Is there a way to manually track a point in motion?
on Oct 18, 2015 at 6:36:38 pm

I keyframed my clip all the way through, and the track stayed on the point, but I noticed unlike other tracks that have actually worked with the automatic tracking feature, there was no red path line. It didn't work when I tried to match move an object in the clip either. Is there a way I can get that red tracking path line in so it works?


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