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.