Motion Capture.

Motion capture has improved film drastically. Using motion capture, it is possible to track an actors movements and gestures and apply them directly to a 3D model. This makes the characters movements more life-like and realistic. It works particularly well when the character being animated is within a scene or interacting with actors in a live action motion picture, for example, if a character is a mythological creature like a troll or an ogre and the entire character is needed to be created digitally.

It also makes the animation process a lot faster as each position is not having to be key framed by hand individually.