The rest position settings for each constraint are located in the constrained object’s constraint attributes. The rest position is where in world space your constrained object is positioned when its target weight is 0. See Set Rest Position in the Constrain menu topic for a more detailed explanation.
If on, the rest position is active for the constrained object. If off, the rest position is inactive for the constrained object. Turning Enable Rest Position off does not remove it from the constrained object.
Sets the X, Y, and Z translation for the constrained object’s Translate rest position. These fields are present for only Point and Parent constraints.
Sets the X, Y, and Z rotation for the constrained object’s Rotate rest position. These fields are present only for Orient, Aim, Parent, Tangent, and Normal constraints.
Sets the X, Y, and Z scaling for the constrained object’s Scale rest position. These fields are present only for Scale constraints.