About Traditional Animation
Traditional animations can involve a large variety of hands on media and techniques. These techniques have directly inspired many of the digital animation methods.
In many of the traditional approaches, a series of images are photographed from above, using a camera mounted to an animation stand. This results in images that are upside down. In traditional 3D animations, the camera is mounted to a tripod (for a stationary camera) or rig (for a moving camera).
With both approaches, every keyframe and inbetween frame needs to be photographed - there is not automatic tweening.