Check out this newsroom…
It looks quite futuristic and visually appealing, right?
But do you really think those buildings in the background are real? Or, for that matter, that globe is on a very large screen?
In reality, here’s how an actual newsroom looks…
It’s all green screen. This screen is then populated through digitally-generated elements.
So, what you see on news channels, they aren’t giant-size screens in the background. It’s actually a green screen that’s digitally manipulated with the desired graphics.
This is a very common example of compositing.
Compositing is basically combining visual elements from various sources into one screen in order to create an illusion that all of these elements are a part of the same scene.
In our above example, the green screen is one element that gets replaced by computer-generated visuals. The person reading the news in front of that screen is another element.
A compositing software is used to bring them all together and create an integrated and immersive video experience.
Now coming to your exact question…
“What is the role of compositing in animation?”
Of course, the fundamental definition of compositing would remain the same, which is that it combines visual elements from different sources to make them look like they are part of the same scene.
However, in pure animation, unlike VFX, there’s no live-action. All the images that you see are digitally created and manipulated.
Here’s a very, very basic animation...
It has no background. It has not separate visual elements. The entire animation is on one storyboard. So, here compositing isn’t required.
But let’s take a look at a non-basic animation…
You can see the clouds are moving, the green field/hill is moving, and the sun is moving. So, the animation has multiple visual elements. What compositing has done is integrate these elements together to make them look like one scene.
Now, watch this Pink Panther video…
This animation has so many different visual elements – from characters to the background to objects. These are created individually and then through the process of compositing, they are brought together to create immersive storytelling.
Needless to say, the more advanced the animation video is (with multiple elements), the more difficult and time-consuming would be the process of compositing, which is usually the last phase in the animation pipeline.
That said, there are now exists many powerful (and expensive) compositing software that make the life of compositor artists a bit easier. Some of the popular ones include Natron, Autodesk Flame, Adobe After Effects, Nuke and Fusion 9.
Hope this answered your question.