Each unconstrained component in an assembly has six degrees of freedom (DOF). It can move along or rotate about each of the X, Y, and Z axes. The ability to move along X, Y, and Z axes is called translational freedom. The ability to rotate around the axes is called rotational freedom.
Whenever you apply a constraint to a component in an assembly, you remove one or more degrees of freedom. A component is fully constrained when all degrees of freedom (DOF) are removed. You are not required to constrain completely any component in an assembly in Autodesk Inventor.
To verify the DOF of components in an assembly: