Adobe After Effects

Rotoscoping with the Roto Brush

There’s a problem at the midpoint in this comp.

The hand that enters the frame goes underneath the composited image. We need to fix this. In order to do so, we need a layer with just the hand on it. Thinking back to chapter 4, we can isolate objects with masks. However, this is footage—we need a new mask shape on every frame.

Animating a mask to span multiple frames is called rotoscoping. Keyframing a mask path over a long video can be an incredibly tedious process. Luckily, After Effects has a tool that will make this much easier for us, called the Roto Brush tool.

First, a Little Setting Up

The hand needs ...