Nondestructive evaluation (NDE) contributes to the integrity and safe operation of engineered components and structures, providing information on the presence of defects and the actual conditions during production and operation, as well. The use of appropriate models for NDE techniques, which are capable to predict the output of an NDE system quantitatively, have an important impact on the reliability and efficiency of modern NDE methods. During the last years there has been remarkable progress made in the development and the use of models to describe the total transfer chain of NDE systems. Actually there are available a number of CAD-based NDE simulation tools for several standard NDE techniques such as ultrasonics, eddy currents, and radiography. It turns out that the following areas are of major interest for the application of NDE simulators: — the use of models during the design process to ensure the inspectability of the engineered components at the earliest possible stage — the use of models for feasibility analysis, e.g. for damage analysis to investigate whether the producer or the user of the component have considered all state-of-the-art NDE techniques to ensure the safe operation of the component while avoiding its damage, or to investigate the applicability of standard techniques for specialized testing problems — the use of models to develop new NDE techniques, extend their measurement capabilities including model-based data interpretation and 3-dimensional reconstruction of material properties, or to optimize standard techniques for special applications — the use of models for reliability investigations and validation tasks in terms of the prediction of probability of detection (POD) to describe the potential capability of the NDE method excluding human factor, the definition of parameters essentially influencing the response of the NDE system including their accessible ranges, or the application of models as a part of a modular validation procedure — the use of models for education and training purposes where interactive training tools will improve the learning experience, and reduces the time on task for students and the material costs as well</p