Creating the main track and offset tracking

- When we have to track objects we're not always going to be lucky enough to find an area exactly around the place where we want to track. In this case, we want to track the cup in here so that we can add steam and also so we can create a mark shape around the edge of the cup. The tea box, itself, comes all the way and covers completely this area of the cup where we want to actually track. So for quite a few of the frames from frame 14 all the way through to frame 24/23 our shape is completely hidden by the tea box.

So it's here where I'm going to use a little technique called offset tracking. So the first thing I'm going to do is create an x-spline that goes around the area where i want to track. And I'll come over to my layer controls and I'll call this one cup track. Now in this case, I don't want to track in share or anything like that because when we start to add the steam in we're not going to be using share, we're not going be using the corner pin to do any sort of work. So share is just going to be a little too much information than we really need. I don't expect there to be any rotation but just in case I'm going to leave that turned on as well.

Everything else, I'm going to leave at default. And I'm just going to track this through. Whoa, there we go. Right up until the section where my box just hammers through and completely ruins my track. So I'm good up 'til frame 12. And just for the sake of good order, I'm going to come in to the dope sheet to select the other two frames. The other two key frames on 13 and 14 and just delete those.

Even though my original shape is to get completely hidden by this box because the tracking data and the shape data are two different things, What I can do is then just move my shape on to an area over here which is co-planar. So maybe something like the edge of the tea cup here which probably is sitting around the same plane as my cup is at the moment there and then I can track that forward until I can see my cup properly again.

Let's come in and we'll bring that back and let's track that forward again. So if we play that back and have a little look at what's going on here, you'll see that my shape, itself, seems to be darting around all over the place. Let's come back to the first frame, turn on my surface, That is of course the only place where we can really tell what the tracker is going to do. So let's come in and then hit play there.

And we should see that that is working absolutely fine. It's working fine right up until, actually a place where I didn't expect it to have any issues which is around about the end there. You can see it starting to move in. So what I'm going to do with this one here is turn my outlines back on, my layer outlines back on, turn my surface off again. And here I'm going to re-track this but I'm going to turn my motion to small motion and just re-track that again.

Let's take a look at the surface, turn off the outlines one more time. And there we go, now we've got a nice consistent track and we can check that is also consistent now because I'm going to use that track. Let's turn off processing and turn on the lock. So we're going to use this track now to drive the creation of our track map.

And we'll turn off visibility on that as well and I'm going to use a Bezier mask here because this Bezier mask is going to be a bit better suited for this type of nice, sweeping line. Remember, point my handle in the direction where I want it to go. So control click here, I'm not going to be too accurate on the other areas down here. I just want to make sure I've got a mask going on around the lip of the cup right to there.

So let's call this one cup, m for cup mask and link this now to the cup track, play it forward. It's looking good, let's check how it looks stabilized. That's also a good way of checking that out. We can see there's a little bit of slippage going on from there so I add a key frame here.

And I'll just control click on the handle just to adjust the handle up without affecting anything else. And this is probably going to be a little bit of adjustment to be made because of the track out there. And that will compensate for the small amount of perspective shift that we have going on. There, so we destabilize that one more time.

Hit asterisk on the number pad to zoom us out and that looks pretty good. So now we've created our first track that we're going to use to track the steaming and we've used that same track to drive the mask that we're going to use to keep the steam into the cup itself and we've used offset tracking on our cup here so that when things got tricky and objects went out of view we were able to track an object that was co-planar to our original object. So it sat int he same plane as our original object and take any of the hassle out of creating a nice, accurate track.