The present disclosure proposes a detachable second apparatus coupled to a first apparatus for determining a first three-dimensional shape of an object located on a reference plane and configured to determine an angle of an upper surface of the object with respect to the reference plane. The second apparatus according to the present disclosure includes a first light source configured to sequentially irradiate one or more first pattern lights having one phase range, a beam splitter and one or more lenses configured to change optical paths of the one or more first pattern lights so that the lights corresponding to respective phases of the phase range reach a partial area of the upper surface of the object in a dispersed manner, a communication interface configured to communicate with the first apparatus, and a first processor electrically connected to the first light source and the communication interface. The first processor is configured to obtain, from the first apparatus, first information on one or more first reflected lights generated by reflecting the one or more first pattern lights from the partial area and is configured to determine the angle of the upper surface with respect to the reference plane based on the first information.