In order to create a new alpha channel for a specific sequence or video, a rotoscoping artist uses a set of animation tools in the software to trace the object. Contrary to images generated by the computer, which can easily add an alpha channel to photos but in this, the footage is taken from a camera that has no alpha channel.
Therefore, a rotoscope artist will have to create this alpha mask manually by tracing the elements in the video. A rotoscoping artist creates and animates various forms around an object to conform to the motion on each platform.
The rotoscoping process may take hours or even days to complete depending upon the difficulty of the shot. Having blue and green displays can make it much easier to arrange different elements into a scene, but not every shot will benefit from blue and green displays, so rotoscoping still has a major role to play when creating visual effects. Because rotoscoping is used in almost all movies and TV shows that use visual effects, the role of rotary artists in the VFX pipeline is not surprising.