After Effects — Rotoscoping and Roto Brush
Rotoscoping is a technique to create an animation by tracing a real footage frame by frame. The technique was invented in early 1900s to help animators to reproduce realistic movements. Fleischer brothers, who invented the technique, and Disney, which incorporated it after the original patent was expired, didn’t simply reproduce the reality into animations, but developed unique animation styles by emphasizing elements in real movements.
Isolating an element using Roto Brush
Roto Brush in After Effects help animators to isolate an object from a footage, so the object can be composed with another footage or background, which are called Mattes.
Although Roto Brush is an intuitive and powerful tool to group moving objects, it is processor intensive. Hence, it is important not to keep your footage unnecessarily large nor long, and the contrast between objects and background should be high in order for the tool to do great jobs for you.
