The Discrete Element Method (DEM) is becoming widely used to simulate particle flows. It is a versatile and powerful tool. Its main limitation, the CPU time required, is becoming less critical with the development of computer technology. Most DEM simulations consider spherical particles in three dimension (3D) or circles in 2D. Several researchers are developing models of non-circular particles in 2D, but there are few applications of DEM to non-spherical particles in 3D granular flow. This paper proposes a technique of sphere intersection for particle description that is applied here in 2D and 3D. It then describes a known technique of sphero-cylinders in 3D and applies it to small-scale simulations of discharge of frictionless particles, modelling contact normal forces, from a hopper. Aspect ratio for these particles is shown to have a negligible effect on discharge rate. Simulations in 2D showed that the disc-shaped particles discharged 40% faster than the circular particles. Program code tests are described to check the complex model of rotational dynamics for non-spherical particles in 3D. (C) 2003 Elsevier Ltd. All rights reserved.