Hello, this is Eric D. Kirk for mamoworld.com and welcome to this After Effects tutorial
about using stabilized precomps with our extension MochaImport+ and the mocha plugin that is
bundled with After Effects.
As an example, we want to manipulate the building here and with the help of MochaImport+ this
will be surprisingly simple and a lot of fun!
We start with a composition that just contains our clip and launch MochaImport+ from the
Window menu.
With our clip selected, we now choose the mocha version we want to work with and click
on “Track”.
Since we’ve chosen a plugin version of mocha, this creates a mocha effect on our layer.
For standalone versions of mocha, MochaImport+ will send the clip to mocha instead.
In the effect controls, we click on the “MOCHA” button to open the mocha user interface.
We are working with the “essentials” user interface, which is designed for beginners
- if you are an experienced Mocha user, or are familiar with the user interface of older
mocha versions, you can also switch to the “classic” user interface which contains
many advanced controls.
Now we draw a mask roughly around the area that we want to manipulate and make sure that
in the tracking options also perspective is enabled.
With perspective enabled, tracking is slower, but often more accurate.
Now we click on “Track backwards” since we are currently at the last frame and then
wait until the track is finished.
Then we close mocha and save the changes.
To load the tracking data into MochaImport+, we first click on “create track data”
on the mocha effect and then select the mocha layer, from which the track data should be
loaded.
Then we click on the “load” button to load the data from the plugin effect into
MochaImport+.
Now we can create the stabilized precomp.
Stabilized precomps are always created on a duplicate of the background layer.
So we duplicate it and give the duplicate a meaningful name like “wall”.
Then with the wall layer selected, we choose “stabilized precomp” and click apply.
In this dialog we can choose the corner pin effect that should be used to create the stabilized
precomp.
We use the default “CC Power Pin” here.
Also make sure that the “live expressions” option is enabled, because it will allow us
to adjust the region that is included in the stabilized precomp.
Finally make sure that the resolution of the precomp is set to 100%.
Lower resolutions only make sense if you create stabilized precomps for very small portions
of your image and want them to render a bit faster.
If we hide the background layer for a second, you can see that the stabilized precomp looks
exactly like the background, but only contains the region that we tracked.
It also moves with the track.
In the effect controls you can see that there is a corner pin effect on the layer.
It moves with the track, but since we enabled the “live expressions” option, in only
has a single keyframe.
We can change this keyframe now such that it contains exactly the region we want to
manipulate.
We set the region such that the edges of the corner pin are parallel to the wall.
Then, on the left side we make it a bit larger, since we want to extend the wall in that area.
Also this new region moves accurately with our track now.
Now let’s double-click the stabilized precomp layer to open the precomp.
Inside the precomp we can see the region that we have just chosen and it is perfectly stabilized.
Therefore, it is easy to make any kind of manipulations here now.
Let’s duplicate our background, for example, give it the name “Window” and add a mask
around this window here.
Now we can move it over and maybe scale it down a bit and in just a few seconds our building
has an additional window.
If we go back to our main composition, you can see that the window is visible there,
too, and moves accurately the the track.
Now we go back to the stabilized precomp and add some more complex manipulations.
We duplicate the background again and name the duplicate “wall extension”.
This time, we draw a mask around this entire area here and move it to the left.
We add a second mask here to give this part a nice, rounded shape and set its mask mode
to subtract.
Here, the edge is a little bit visible, so we add some feather to our masks to soften
the edge a little bit.
So this is how it looks like in our stabilized precomp and here is the result in our main
composition.
The great thing about this workflow is that you can really do any kinds of manipulations
inside the precomp - you can use the clone stamp tool, bring in other images, do any
kind of compositing work!
Inside the stabilized precomp you don’t need to care about the movement anymore and
everything you do is automatically also visible in the main comp.
If we compare what we created so far to the final result, you can see that in the final
version there is also bit of the bottom visible in this area here.
This is a bit tricky tricky to create but helps a lot to sell the effect.
What I actually did was simply adding a solid with some noise.
A few mask keyframes where all I needed to animate its shape over time.
In order to get the perspective right, I looked for parallel edges in the scene and simply
followed their direction.
That’s the end of this tutorial!
I hope it gave you some idea what you can do with stabilized precomps in MochaImport+.
Again, this is Eric D. Kirk for mamoworld.com - see you next time!