Computer Aided Design (CAD) and Computer Aided Engineering (CAE) are two significantly different disciplines, and hence they require different shape models representations. As a result, models generated by CAD systems are often unsuitable for Finite Element Analysis (FEA) needs. In this book, a new approach is proposed to reduce the gaps between CAD and CAE software''s. There is based on new shape representation called mixed shape representation. This later supports simultaneously the B-Rep (manifold and non-manifold) and polyhedral representation, and creates a robust link between the CAD model (B-Rep NURBS) and the polyhedral model. The both representations are maintained on the same topology support called the High Level Topology (HLT), which represents a common requirement for simulation model preparation. The chapters cover the geometric models involved in CAD and CAE and the associated methods and tools for Finite element model generation. The software implementation of the integration between CAD and CAE is also developed in this book. The book is an excellent industrial reference, as well as a student text.