Click on any phrase to play the video from that point.
[♫Mysterious music]
[ADOBE TV][Presents][Colin Smith][in...]
[Stupid Questions]
[Male speaker] No stupid questions. [Static]
[♫End music]
The Roto Brush is a fantastic tool in After Effects.
It's used to select a segment, and remove the background
or select the background, remove the foreground--
whatever you're selecting, it's a great tool.
It works on things that are static or they're moving around.
It's just that sometimes you need to help Roto Brush.
So this demonstration is just a couple of tips
to make working with the Roto Brush easier.
So a few things to remember that will just help you
and stop those crazy things that happen when you do the wrong thing.
Let's have a look.
Here, I've got a quick little video
of our little friend here,
and I'm picking something that's--you know, a little bit hard to Roto
but nonetheless, it's going to be our test footage.
I'll double-click; it opens up in the Layers,
and I'll grab the Roto Brush up in the top.
And the first thing you need to do is change the brush--
and make it pretty big.
So I'm just holding down the Command key or the Control key, on Windows--
clicking and dragging with the mouse.
Do not go around the outside edge.
Just go through the main body of whatever you're selecting.
So if you're selecting someone's arm, don't think about going around the edge.
Think of the skeleton that runs through them,
and that's what you're selecting.
It's not meant to be perfect the very first time you select it.
As you can see here, it gets some of the guy--but not everything.
So let me add a little bit more--
another big stroke, another big stroke--
and as I get down to these smaller ones
or the tighter edge of the area,
I'm going to drag this down and make it smaller; click along.
It also doesn't hurt to come out into this area of the background I don't want,
hold down the Option key--Alt on Windows--
and click and drag, even before it starts making mistakes--
see, it grabbed that area down there, I didn't want.
So initially, down here you'll notice that this little brown area--
that is the base frame.
Your job is to make this base frame as good as it can be.
Everything else is based on this.
So don't get this okay, and then start working in another area.
Stay inside, and tweak the edges.
The other thing you'll see is a warning that says:
Draw Roto Brush strokes at full resolution.
And down here, I've got a resolution of 50 percent--
so it wants me to do this at 100 percent.
Now, I'm working in After Effects at a pretty
low resolution screen capture right here;
so chances are--if you've got a 24 inch monitor,
you're going to have more than enough room to stay at 100 percent.
So again, make my brush even smaller and start dragging near these edges.
And you'll see--occasionally, it's going to capture a bit of that stuff you don't want
so you're going back and forth in these areas.
Over in my settings, the Propagation--when I turn this down
on this particular file, I found that the Search Radius--
all right, take that down to 5
so as it's searching, it's not looking too far away from that area.
And the results were just a little bit better for me.
I'm going to have to really add a lot of blur inside here to capture some of this hair.
It's not about to capture all of it perfectly
but for this little motion file here, it's going to be fine.
Again, I'll look around the edges.
You know--here's a typical problem:
we've got the light-colored grass, the light-colored fur--
they're absolutely the same color;
so you're going to have to go in there,
and make sure you've got those edges.
So a lot of these little areas are a little bit tricky
but I still go down inside and make sure I've got it.
A little bit more, a little bit more--maybe some of that hair is mixing inside there.
All right. The other thing that I found, in helping to control this,
is over here--on the Edge Detection, where it's set for Balanced--
if I change this to Favor Current Edges, you're basically
telling After Effects: Look, I've already done a good job at making my selections.
When you go and propagate this and make new frames,
base it on what I have--not on--let's look the other option--
on the Predicted Edges.
So I don't want your predictions, I want my edges that I've created.
Okay. So again, it's telling us--down at the bottom, it's going to keep warning us
that we should be at 100 percent--
but I'm just going to leave it here.
So let's look down at the bottom.
Again, the very first frame is our base frame,
and After Effects draws 20 frames on both ways.
You'll notice that these arrows face in one direction.
This one goes to the right, and that one goes to the left.
Basically, it does not hurt to start playing this file and watching it.
And you can see areas where it's having a problem.
Go back to that area, and fix it from there.
Don't go out past that area, and fix it.
Because here's the problem:
Let's say my first base frame is zero,
the error occurred at 4--
so you should fix it at 4.
If you pass 4, and you go to 15--
and you go back to 4, and you edit 4--
15 will change everything, back.
So you want to work from the base frame, forward--
and from the base frame, backwards.
So I'm just using my Page Up and Page Down keys on my keypad,
and I'll just Page Up until--
whoa--you can see, it's getting a little bit away, right from there.
Almost instantly, it's starting to move away.
So again: Option,
Paint, down a little bit.
Every time we've got a little problem in there, you just hit that.
And it's much easier than having to go through the whole thing.
Oh--we've got some around the eye there,
but I think you get the idea.
It's not going to change anything too drastic
because I'm moving in smaller increments in here.
And you might get a little impatient and try to jump ahead,
but you'll only pay the price if you don't have that kind of patience.
Oh--okay, not a problem.
Again, it's starting to blend the brown of the fur into some of that grass
and it might be okay for me to start to use a smaller brush.
And then, of course, you've got to go back--oops--
down in here.
Let me go back in--and as we're caching this stuff,
it's going to be a little bit faster.
So if I started to jump out, past this--
all the way over to here--
and now I start to make changes,
these changes will be affected all the way back.
So it will affect some of the ones that I've already done.
That's why you're working from 1 to 2 to 3--
and you do the exact same thing back here,
on the other side.
So we start working backwards--
same thing, going backwards in our frames.
And see--again, a little bit of the head in there, a little bit of the eye;
maybe make my brush even smaller.
Remember, we can get this all the way down to 1 pixel, in size.
And we might need to do some additional work with different brushes,
but I think you get the idea.
So let's go there.
And you'll see that everything is much more predictable
when I'm working from the base frame, out--
and the the base frame, out, on either side.
And then when we're done, we can turn on things like Refine Matte
and then Soften this Edge, and you know that's going to--
and Feather this, and that's going to start helping us blend into that outside edge
and just get a much better Roto.
So Roto Brush really is a fantastic tool.
It's a robust tool; there's just a few settings inside there you need to be aware of.
And have a little patience, and pay a little attention--
make sure you're changing your brush sizes.
Make sure you're selecting in areas outside that you don't want,
even if it hasn't gone and painted in to that area.
Just start telling Roto Brush: Don't look here, don't look there;
this is the stuff I want.
Fine tune things, and you're going to have your Roto Brush work
looking much better, much quicker.
[♫music] [Presenter/Music] [Colin Smith]
[Executive Producer][Bob Donlon][Producer][Karl Miller]
[Director/VFX][Kush Amerasinghe][Post-Production/DP][Erik Espera]
[ADOBE® TV Productions]
