In automotive FEA analysis, there are many components or assemblies which can be simplified to two-dimensional (2D) plane or axisymmetric analytical problems instead of three-dimensional (3D) simulation models for quick modeling and efficient analysis to meet the timing in the design development process, especially in the advanced design phase and iteration studies. Even though some situations are not perfectly planar or axisymmetric problems, they may still be approximated in 2D planar or axisymmetric models, achieving results accurate enough to meet engineering requirements. In this paper, the authors have presented and summarized several complex 3D analytical situations which can be replaced by simplified plane axisymmetric models or 2D plane strain analytical models. Several numerical case studies presented in this paper demonstrate that plane axisymmetric and 2D planar models can provide efficient, reliable, and accurate analytical results as compared to the analytical results of equivalent 3D models. These case studies are intended to be used as reference for auto industry and CAE/FEA peers.