An unpacking system for use in an apparatus for producing three-dimensional work pieces by irradiating layers of a raw material powder electromagnetic or particle radiation comprises a supporting structure which is configured to support a building chamber arrangement. The building chamber arrangement comprises a building chamber accommodating a carrier, the carrier being configured to receive a three-dimensional work piece produced from a raw material powder by an additive layering process. A lowering mechanism of the unpacking system is configured to apply a driving force to the building chamber so as to lower the building chamber relative to the carrier until a three-dimensional work piece received on the carrier can be removed from the carrier.