3D
models are often animated for some uses. For example, 3D model
are heavily animated for use in feature films and advertising.
They can be animated from within the 3D modeler that created
them or externally. Often extra data is added to the model to
make it easier to animate. For example, some 3D models of humans
and animals have entire bone systems so they will look realistic
when they move and can be manipulated via joints and bones.
