The invention relates to a computer-assisted method (1) and a device (C1) for generating a digital representation (17) of a technical structure, in particular an electric motor, and to a corresponding computer program product (1, C2). In the method (1), a domain-specific model based on digital geometric data of the components (2, 18, 19, 20, 21, 22) is provided. Thereby, a model reduction is carried out, in which a domain-specific model is converted into modal coordinates, in which a spectral representation of the component (2, 18, 19, 20, 21, 22) is determined by means of a corresponding modal analysis. Based on this, the corresponding state space representation is generated as a reduced-order spectral model. In order to integrally simulate the technical structure, the spectral models are coupled to each other to form a digital representation (17) for simulation, which describes the performance of the technical structure across domains.