In this tutorial we're going to show you how you can track the front of a tablet or iPad
and then replace that surface with some kind of futuristic UI.
We're going to look at the UI in another tutorial but right now we're going to look at the tracking
which is a bit problematic here because a hand moves in front of the tracking markers.
But there are some techniques you can use to get round issues like that, so lets do
this.
So here we can see the futuristic Westworld-style UI we're going to try and track onto this
iPad.
It actually tracks really well but we're not looking at one of the more problematic areas
of the footage.
So let's go and have a look at that.
So yeah, we have these great tracking markers to track off but unfortunately Josh moves
his hand right over one of them and then moves it away.
This instantly makes this shot massively harder to track.
So how are we going to get around that?
Well, there's a few techniques we can use but let's do the easy stuff first.
So first of all we're going to work on tracking the left-hand side of the footage.
So we add a tracker to the clip and then we want to make sure it's a double-point tracker.
This adds two of these little boxes over here, zoom in a little bit.
We then have the red and green boxes that we're going to place.
Put that on the bottom and then right over that feature, the cross of that feature, we'll
expand out the red area, that's what we're tracking and make it expand the green area,
that's the area it's going to look in.
So we'll put one at the top here as well.
And then we're just going to play forward.
As you can see I've kind of started half-way through the clip.
This is because I find the features that I'm tracking to be really sharp here and we can
always track forward and backwards.
Skip back to where my track started and then press the track backwards button.Here we go,
its already done all of the tracking.
And yeah, it's a really solid track and it's looking good.
So I'm going to name this tracker because we're going to make so many of these in this
tutorial.
I'm going to call it 'Left Edge' and then I'm going to create a new 'Point' and I'm
also going to call that 'Left Edge'.
Now what we want to do is go back to our Left Edge track, select rotation and scale and
then select that new Left Edge Point and click apply.
This has transferred that new tracking data over to the point.
Now in the viewer - there you go, you can see it's tracking on nicely.
This is exactly what we want so we're going to do this top edge no, exactly the same principle;
we add a tracker, we make sure it's a double points tracker then we're going to move these
over these clear, very easy to track points.
Again, the red square is what we're looking for, what the software is trying to find,
and the green square is the area it's going to look in.
Get that right on the center there and expand that out as well.
And again, I'm not on the first frame because we don't need to be, and let's just track
forwards.
Again it's finding that very easy, keeping those green areas as small as possible makes
the tracking faster.
And now let's go back to that first frame, I've just expanded it out so I can see where
the keyframes are, and track back to the beginning.
Again we've got a very solid track.
So I'm going to do the same thing; I'm going to call this Top Edge and then I'll make another
new Point and, surprise surprise, I'll call that Top Edge too.
Now we go back to the track, we make sure the rotation and scale are clicked, change
the layer to Top Edge and click apply.
Now we're going to try and do the complicated track.
That bottom right point.
Again, it needs to be a double points tracker.
And what we're going to do is, the one that's on the left here, that's the first tracker,
we're going to move that to our position in the bottom right, and then we'll put the other
one, the second one, in the bottom left.
We'll expand it out and do just as we have before, but rather than pressing Play this
time, we're going to step, frame by frame, to make sure we get exactly what we want.
So first of all I'm going to step backwards because I'm not quite at the start of the
clip.
There we go, that tracked nice and easily.
And now I'm going to go back to where I was, which was here, and start tracking forward
until the hand moves in the way.
So we're all good here.
Now the hand will begin to move and it'll start to cover the tracker.
Now what we're going to do is we're going to leave the point exactly where we want it
but we're going to change where the feature is to something else we can continue tracking
that isn't being covered by the hand.
So I'm going to move it to the Home button of the iPad, I do this by holding Alt when
I drag, therefore, the actual position stays in the same place.
I'm now going to move forward a bit and I think actually maybe the point in the center
is a better one so I'm going to move it up the there, again clicking Alt when I drag
it so it doesn't move the origin point, and then I'm just going to keep on tracking forwards.
Now the important thing is that we're going to want to get this track back on that original
point as quickly as we can so that we don't just have too much drift in our track.
Here we go, I've moved it back and now I can just press play forward and let it do the
rest of the tracking.
Now this has done pretty well for us.
In fact, very well.
But, if we zoom in a little bit and look at it more closely we do have some issues here,
there is some drift.
See we've moved a little bit away from that central point.
So how are we going to get around this issue?
Well let's, first of all finish off where we are, let's call this Bottom Edge, make
a Point and we'll call that Bottom Edge as well and as before, we move that tracking
data, rotation and scale, across to the Bottom Edge and click apply.
And now when we go back to the viewer, we click all these points we've recorded you'll
notice one is missing.
This is actually because this was recorded at the same time as our Top Left point so
all we need to do is parent a point to that and off-set it and it'll be in the right position
because the scale and the rotation and the position will all be set from that top left
point.
But what are we going to do about this one at the bottom right?
So it's pretty good and then when the hand is in place we can see it's drifted off to
the right and down a touch.
This is enough to throw off the track basically make the UI not sit correctly on the iPad
and everyone will be able to tell so what are we going to do to fix it?
Well first of all I'm going to make another Point and I'm going to call this Bottom Edge
fix.
We're then going to parent this to our bottom edge, making sure to reset the transform so
it sits exactly on that track.
And all we're going to do is look at that original track and at what points we know
the track was in the right place and then when it was being covered up and add our own
keyframing to fix this so first of all I'll try and tweak the first couple of keyframes
then I'll move all the way to the end, we can see how far it's off, and we'll move it
back into position.
All this is going to do is animate between these points of reference that we know and
hopefully that's going to be enough to make this a solid track.
So I'll just do a bit of tweaking here at the start, I should have probably actually
moved the tracker one frame earlier to a good reference point because the blurry hand started
coming in and making it move but it's very easy to correct and now we can actually see
that the tracking is massively better.
And what I'm going to do is I'm going to move that bottom edge point to the bottom of these
so that I don't use it anymore and it's only a reference to move that fixed point around.
Now if we select all these points, the top three, we'll see, we're in a really good place,
all of these points are tracked.
"But hang on", you're saying, "these aren't in the corners of the screen.
How am I going to track the UI to this?".
Well, it's all very simple from here on out.
I'm going to create and then duplicate it four times.
I'm going to call these Top Left, Top Right, Bottom Left, Bottom Right, and then I'm going
to actually start parenting them.
So that bottom edge is actually our bottom right so we can parent it directly.
Make sure to reset the transform otherwise it'll be offset.
That bottom left is actually our Left Edge because our main origin of that was in the
Bottom Left.
And then the top left is actually our Top Edge because, again, the origin of that was
in the Top Left.
And then we have the Top Right which we want to parent that to our Top Edge again.
And then just offset it by dragging it to the correct position because the scale and
rotation of that point were referencing that other point so this should work perfectly.
I'll just move it across and move it down, you can just drag it wherever you want it
here so that's great, we've got our four points now and things are actually very simple from
here on out.
So if we just have a look at all of these all we have to do now is find a frame where
we can see exactly where we want these corners to be, somewhere around here and actually
just drag these new top four points into those corners.
I'm just going to go just a little bit over the edge, that's going to help us out so we
don't have to do any masking or anything like that.
And now if we select these, these are all just tracked in place.
This is exactly what we wanted - of course we'd have to do some masking of the hand.
Let's just drag on the interface shot that we have and then we go to the effects and
we select the quad warp tool, drag that on, and this is as simple as it looks, and each
one of these, we just parent it to the right point and there you have it, it's tracked
on, it sits perfectly on the iPad.
You want to switch on the motion blur and things like that for your final render.
You're going to need to do some masking around the hand but in the next tutorial we're going
to show you how we actually put the animated version of this interface together so you
can have a go at doing it yourself.