Formulation of the constructive assignment. It is the task of the designer to adapt the components of any machine or apparatus as accurately as possible to the intended use. Therefore, for a purpose-appropriate design, the operating conditions must be reliably known. The designer cannot simply create any bearing or gear; instead, they must design a bearing or gear that is best suited for the specified operating conditions. The difficulty lies in the fact that 'operating conditions' encompass a wide variety of influences. For example, one must assume that a rock drill used in quarries remains functional under harsh operating conditions and does not suffer significant damage when dropped. Consequently, the shapes of the same machine part vary with the intended use. A machine intended to be operated by unskilled workers in mines or dusty environments must be designed with different considerations than one used in clean machine halls, maintained meticulously by trained personnel. A motor looks entirely different when used as a stationary machine, a ship engine, or an automobile or aircraft engine, even if the engine power remains the same in all cases. An export machine may sometimes need to be constructed differently in detail to account for transport and repair possibilities in remote areas. In other cases, the intended use may require a machine that operates as quietly as possible, and so on. In teaching machine elements, the focus can naturally only be on addressing the general aspects of calculation and design. The final shaping can only be determined on a case-by-case basis and based on experience.