1. A computer-implemented method for medical device modeling, comprising: accessing an electronic definition for a model of a three-dimensional item and an electronic definition of a three-dimensional spline relating to an internal anatomical volume; determining, with a computer-based finite element analysis system and using the electronic definitions, stresses created by the three-dimensional item along the three-dimensional spline, for different points along the three-dimensional spline; and displaying stress data generated by the finite element analysis system with a visualization system, the display of the stress data indicating levels of stress on portions of the three-dimensional item at particular locations along the three-dimensional spline.