The most important feature of the candidate set of DOF is that the resulting candidate set TAM must provide an excellent representation of the FEM target modes. Since the candidate set DOF TAM will be loaded into GA and GA will select DOF that render the candidate set TAM’s target modes linearly independent, it is imperative that the target mode shapes and frequencies of the candidate set TAM match the full FEM very well. Your GA selected DOF TAM is limited by the candidate set TAM and can not represent the FEM any better than the candidate set TAM. Because the candidate set can include many DOF, it usually is not difficult to achieve a good FEM representation. It is important to check that the candidate TAM is good before using the GA. A Nastran DMAP alter ortho calculates the FEM-TAM orthogonality to assess the quality of a TAM and is also available in TAMKIT.