SUMMARY Hamiltonian models of high‐velocity impact dynamics, based on a hybrid particle‐element kinematic scheme, offer an energy conserving description of general contact‐impact, perforation, and fragmentation physics with applications in a number of important engineering fields. Published work on these models has considered only a uniform finite element mesh, requiring curved surfaces and many target and projectile geometries to be represented in an approximate fashion. In recent research, the authors have developed a new formulation suitable for application to any solid model described by an unstructured hexahedral mesh. The formulation incorporates a new algorithm, which constructs an ellipsoidal particle discretization of the mass distribution described by a general hex mesh and a new density interpolation suitable for use with general ellipsoidal arrays whose particles vary in mass, shape, and spatial orientation. Application of the method in the simulation of high‐velocity impact problems shows good agreement with experiment, for both smoothly graded and deliberately distorted hexahedral meshes. Copyright © 2013 John Wiley & Sons, Ltd.