Hi, I'm Mary Poplin with Boris FX and today we're going to talk about the align surface
tool and corner pinning mismatched resolutions.
We will show you what you do when your screen insert is not the same size as your comp.
For most comps in most compositing software, the host assumes when applying a corner pin
that whatever your insert is will be the same size as your comp.
Sometimes mocha users get confused when their mocha track looks perfect but their ae composite
doesn't match what they are seeing in Mocha.
When a source insert is not the same size as the after effects composition, the data
pasted in from Mocha will be misaligned relative to the difference in the source.
Today, I have some easy solutions to help you deal with various alignment issues.
Normally to get started on a shot, I would select my clip layer and I would go to Effect>Boris
FX Mocha and use Mocha Pro or Mocha AE for After Effects to track this screen.
However, we've already baked that cake for you and we're going to pull it right out of
the oven nice and tracked.
To break down what I did, as this is a clearly difficult track, I made a rough track of the
screen with an increased value for rotation, used the new update to the adjust track module
to correct any drift from the lighting shifts, and used PowerMesh to roto the hand on the
screen.
I linked the pen roto to the adjusted screen track.
And I used a corner pin that supports motion blur out of Mocha to create the screen.
With some blending mode magic, it looks like the screen was on the whole time.
BUT.
This tutorial isn’t about how to track this shot, it’s about how to get the corner pin
into AE correctly, so we aren’t going to focus on the nitty gritty of tracking here.
We can do that in another tutorial.
Let’s talk about Aligning your Surface.
Let's take a look at this screen.
We are going to drag it over the top of our comp and you can
see very clearly this is not the same size as my comp.
That's going to be a problem, and let me show you what that problem looks like.
Let’s align this image to my screen with a quick AE corner pin, and just to make sure
effects don’t duel one another, we will precompose this and move all attributes into
the new composition.
If we now apply a corner pin right out of Mocha, look how this is offset.
Let’s see why that is.
Opening Mocha, you can see the Surface Tool is aligned to the screen.
This is ideal when the insert is the same size as the comp.
However, when you have a pre-aligned screen from your host, you need to use the Align
Surface tool to Fit the Surface Tool to the corners of the clip.
So let’s make sure we are on the same frame we aligned our screen on, in this case, frame
122, and click that Align Surface tool and see how the surface tool snaps to the edges.
Perfect.
In Mocha Pro you can copy the tracking data right from the tracking tab and paste it into
your host on the first frame of your insert clip, but I am going to show you how to apply
this data via the plugin interface because it’s more foolproof for getting the data
to apply correctly.
Let’s save and close Mocha.
Back in the host, I will select the create tracking data button.
A layer controls menu will appear, and I will select my screen track.
This is where naming your layers specifically comes in handy.
I click OK and the menu closes automatically.
Now under the export options dropdown menu, I select “corner pin (supports motion blur).”
In the Layer Export To dropdown, I select what layer to apply this data to, in this
case our screen, and I click Apply Export.
Now our aligned screen will move correctly throughout the shot.
This align surface workflow is the preferred way to composite smaller images into larger
ones, as the data stays crisper than the next method I am going to show you.
Now let’s talk about resizing your insert.
For this next method, we are simply going to force the smaller image to be the same
size as the comp.
We select our insert layer and we use AE to expand the image by selecting layer>transform>fit
to comp and then we use the same precomposition method we used previously, selecting layer>pre-compose>move
all attributes into the new composition to envelope our transformation.
Now I can open Mocha and make sure my surface tool is aligned to the screen.
Once the surface tool is properly aligned, I can save and close Mocha.
Back in AE in the Mocha Plug-in interface, I will select the create tracking data button.
A layer controls menu will appear just like before, and I will select my screen track.
Again, I click OK and the menu closes automatically.
Now under the export options dropdown menu, I select “corner pin (supports motion blur).”
In the Layer Export To dropdown, I select what layer to apply this data to, in this
case our screen, and I click Apply Export.
But because this method requires transforming up from a smaller resolution and back down
again to another resolution, you might find you lose some detail.
For a small screen like this, we can get away with it, as it is a bit easier and faster.
But for a hero screen, I would use the align surface method instead of the fit to comp
method.
In some cases, expanding the insert to fit to comp is the only method that will work,
especially if the surface tool has a lot of z space movement, because that can sometimes
break corner pins in Mocha when the surface tool is too large.
So it is good to have both methods in your pocket for when you need them.
To wrap up here's some compositing tips.
All right, now that my corner pin is correct, I can finish this shot.
I'm going to take my trees painting with my corner pin on it that supports motion blur
and I'm going to add a quick box blur right on top of it at about two pixels.
Now I'm going to use softlight to overlay this over the top of my screen.
This will keep my reflections on my screen, but of course I need to put the hand and the
pen back over the top.
To do that, I'm going to take my mocha layer and click duplicate, drag this above my composited
layer.
I'm going to go to matte, and to see what layers will be applied with my matte, I click
visible layers.
I'm going to select the pen and the hand and not the screen track and hit “okay.”
Now I can either “create a mask” in order to use a native After effects masks for this,
or I can use apply matte and control the feathering right here inside of my plugin interface.
And because I'm using apply matte, the matte will render with motion blur as well.
If we really want to get the highlights of our screen back, we can duplicate our bottom
layer, drag it up, and use a lighten blending mode.
Lighten will keep all of the lighter pixels on top, which has an added bonus of making
the edges of the tablet that she's holding blend into the screen insert.
It also brings back any native motion blur for free from the hand or pen.
Finally, we want to make sure that motion blur is on our screen layer.
We actually don't need it on the other layers, but we only need it on the painting layer.
Because our corner pin supports motion blur, we get some beautiful motion blur right inside
of After Effects.
And that’s it, that’s how you can use two different compositing methods to force
corner pins to behave themselves when the insert is not the same size as the comp.
This method works cross host so long as you account for how the host works differently
from After Effects.
But the bottom line is you must either align your surface tool and use that corner pin,
or expand the insert itself.
If you would like to know more about Mocha tracking, please visit us at www.borisfx.com
for training, user forums, live events, and so much more.