The invention concerns a method for production of a three-dimensional body by successively providing powder layers and fusing together of selected areas of said layers, which areas correspond to successive cross sections of the three-dimensional body, wherein the method comprises the following steps for at least one of said layers: applying the at least one powder layer onto a working area, and fusing together a selected area of the at least one powder layer by supplying energy from a radiation gun to the selected area. The invention is characterized in that it comprises the steps of: establishing an intended beam path that is to be used when fusing together the selected area of the at least one powder layer, calculating a temperature in the at least one powder layer along the intended beam path as a function of a specific energy deposition of an imaginary beam that is assumed to move along the intended beam path, adjusting the specific energy deposition of the imaginary beam along the intended beam path depending on the calculated temperature and on conditions set for the step of fusing together the selected area, and providing, based on the calculations and the adjustments, an operating scheme for the specific energy deposition of the real beam to be used for the intended beam path when fusing together the selected area of the at least one layer.