Joints and Degrees of Freedom

Mocs can look stiff when the joints have too few degrees of freedom.

Each direction that a joint can rotate is called a “degree of freedom” (DOF).

Generally speaking, only the knees and elbows have a single degree of freedom.

The neck, shoulders, and hips have three degrees of freedom. The easiest way to get a full three degrees of freedom is to use ball joints (or equivalently mixel joints). You can also get three degrees of freedom using more complicated sub-assemblies built from bar and clip type pieces.

The wrists and ankles are not full ball joints, but still have a decent amount of freedom to move. While you may be able to get away with building something that only has two degrees of freedom, you can get more natural poses by also giving these joints three degrees of freedom.