Specifies whether or not you can directly manipulate an object’s constrained channels. For example, when the point constraint’s Lock Output attribute is off, you can change the position of the constrained object without having to move the driver object.
When a constrained object’s Lock Output attribute is on, you can only manipulate its constrained channels by transforming its driver object. When a constrained object’s Lock Output attribute is off, you can directly manipulate its constrained channels, without having to transform its driver object.