Character rigging is the process of adding joints, musculature and other anatomy to a character model, and facilitating the control of these through handles or controllers for the animator. In short, think of making a puppet in a 3D software. The process involves not just sculpting a model for the character, but also making it ‘animatable’ for the animator to be able to use it to create poses. Without this ‘animatability’ the model is a simple, dead, expressionless sculpture. This complex process of rigging comprises of, but isn’t limited to understanding the anatomy of the character in question, knowing the workflow of the animator, and applying this information within the realms of the software to create a character rig.
Animation by Nick Whitmire: