This thesis addresses implementation of the design knowledge in 3D computer model of transformer's cable box. Design knowledge implementation based on the existing knowledge system ensured that particular knowledge can be stored and reused again. Systems that reuse design knowledge can increase the company product efficiency and can shorten design time of the product. By using stored design knowledge designers are spared from tedious repetition of similar tasks. After an introductory discussion design knowledge used in design of the transformer cable box are analyzed and described. In the following chapters parametrization of the basic parts of the assembly is described as well as optional components whose role is to simplify and accelerate modeling process. Using the skeleton model as the basis for the model of the product the information stored in the parts, that are part of the skeleton, can be used to define the underlying design framework of individual components and assemblies. Usage of the skeleton method creates a very stable model that allows fast and efficient interaction with the constructor. In the finishing chapter test results of the proposed solution were described and elaborated. Software that was used during the preparation of this work is: Catia V5 R24, which was used for modeling, implementation of the design knowledge and creation of the technical documentation.