## 7 Conclusions  
Digital twins are increasingly being used in the industry. They are usually built from different partial models, which are then applied depending on the context. Various exchange formats are used to archive partial models and transfer them between multiple systems from different contexts, such as CAD, CAM, and CAE. The data integrity of digital twins is essential. Providing and processing high-quality data still poses a severe problem. Furthermore, exchanging information between different, partly divergent systems is a frequent source of data quality issues, even though all the information required for correct processing is potentially available in the exchange file. This paper presents a method for systematically improving the compatibility of exchange files by adapting stored objects (\"items\"). It is first necessary to determine the item structure in the source and target systems, as well as to define the structures generally. A comparison of the structures enables the identification of error-causing differences. For this purpose, we suggest five conditions (homogeneous, heterogeneous, positive, negative, and neutral) when performing a comparison. Based on the determined structures and conditions, this paper highlights the adaption of items to ensure faultless processing. After explaining the approach in general, we demonstrate the use of the method based on two diverse use cases from differing domains. The first example is the exchange of a sketch between the source system Creo and the target system Catia using a STEP file in the field of CAD. The second example is the transfer of a meshed retaining ring between the finite element mesh generator Gmsh and the FEM software Z88 via an INP file. As Figure 15 shows, the initially wrongly colored sketch can be correctly interpreted in Catia after applying item adaption. The three steps of the method can also rectify the initially non-functioning data exchange of the retaining ring. However, we want to highlight the following conclusions:  
* Various norms, standards, and approaches uniform the exchange of data. Neutral file-based exchange is widely used, for example, in the context of tools, according to DIN 26100. The influences on data exchange and structure are manifold, which can be a source of compatibility problems. One primary influence is the different implementations of the routines in the pre- and postprocessors of the source and target systems involved during data transmission. * A way to solve these transfer problems is to adapt information internally, directly at the file level, which minimizes the conversion process, as only necessary information is modified. Since compatibility problems are mostly context-dependent, heuristic-based methods are suitable for solving compatibility problems since the distinct issues can be described precisely. * Specifying heuristics allows us to extract and adapt relevant objects with absolute certainty. A precise procedure is necessary because postprocessors usually require a unique data representation. * A challenge, however, is that expert knowledge is necessary to specify the required rules, especially for complex items. Nevertheless, item adaptation is especially suitable for standard parts, such as tools, which are characterized by a relatively small number of features but a high number of variants. The shown approach is ideally suited for automation. It is possible to dynamically determine item structures from transfer files and generalize them regarding file-independent processing. However, there is still a significant challenge in detecting general item structures in the first step of item adaptation, especially when the units of interest become more extensive. Obtaining these manually demands an elaborate, time-consuming discovery process. Since the structures are based primarily on standardized formats, it might be possible to use automatic methods, such as machine learning algorithms, to work out relationships. In this course, validation for different use cases is beneficial.