In CAE analysis of cylinder bore distortion, valve seat distortion, valve guide-to-seat misalignment and cam bore misalignment, nodal displacements on the cylinder bore inner surface and on the gage lines of valve seats, valve guides and cam bores are typically output. Best fit cylinders, best fit circles and best fit lines are computed by utilizing the output displacements of the deformed configuration. Based on the information of the best fit geometry, distortions and misalignments are assessed. Some commercial and in-house software is available to compute the best fit cylinders, best fit circles and best fit lines. However, they suffer from the drawback that only one best-fit geometry can be computed at a time. For example, in the valve seat distortion analysis of a typical 4-cylinder, 4-valve engine, 16 best fit circles are needed. Performing the valve seat distortion analysis by using the commercial software would be tedious and prone to error, since 16 best fit circles have to be computed one by one separately and data transfer as well as the intermediate computation has to be done by hand. This manuscript presents an object-oriented approach to the solution of the above problems. Common operations of finding the best fit geometry are designed as classes. By instantiating these classes, the best fit geometry can be computed automatically and the final distortions and misalignments of all cylinders, valve-seat pairs and cam bores can be assessed automatically in a unified software framework. The presented technique can substantially save the post-processing time and avoid common errors.