Numerical simulation that will capture the complex behaviour of rock fragment systems, e.g., in mining and civil engineering, requires both the computational mechanics capability to model particle interactions between complex shapes and an associated means to represent the kind of arbitrary or angular geometry relevant to problems involving rock fragments. This paper is concerned less with the modelling and more with the representation. Here, we focus on representation geared to 'soft contact' modelling using either combined finite-discrete element (FEM/DEM) methods, or non-spherical DEM methods such as multi-sphere approximations of irregular geometry. 3D laser ranging (LADAR) is used to capture astonishingly realistic rock aggregate geometries. We report on the work flow procedures to generate computationally meshed virtual particles for modelling. The design of a shape library and a suggested procedure for selecting virtual particles for input to FEM/DEM or DEM models is discussed together with the use of inertia moments for shape descriptors. Use of the shape library for shape descriptor analysis is also illustrated. DEM simulations of packing using irregular particles from the shape library are presented. (C) 2008 Elsevier Ltd. All rights reserved.