The design of mechatronic devices is a demanding process not only in terms of the time required but also of the demands placed on the knowledge and experience of development workers. The aim of this research and development was to create suitable procedures, algorithms, and databases of 3D models, with the help of which could this process be significantly shortened and simplified. The results of the development are a software tool for the design of electric drive units, procedures for creating 3D models with the possibility of using the SolidWorks software API, methods for automating the creation of assemblies of 3D models and a description of the knowledge database in which various data and algorithms are stored. The benefits of the proposed procedures, the Drive Picker software tool, and the knowledge database, are demonstrated on the design of a robotic arm with 5 degrees of freedom. Despite the complexity of the preparation of documents needed, it turns out that the chosen approach can significantly speed up and simplify the design of mechatronic devices.