A Modal FE Body represents a flexible body with a reduced degree of freedom of modal coordinates. This type of body is modeled by importing an FE data file and a modal data file in a mesh. The degree of freedom of the body is determined by the number of modes. A Nodal FE Body is an accurate method to analyze the motion and deformation of a flexible body, but it requires significant computer resources. If a system experiences a small deformation, and loading and boundary conditions do not change significantly over time, you can use a modal FE body instead of a computationally expensive nodal FE body. If loading conditions are changed over time, such as with a contact problem, this is not a good method to pursue.