Recent advances, accelerated by the application of computer technology, allow numerical characterization of particle shape in two dimensions. However, characterization of three-dimensional (3D) particle shapes is still largely an unresolved problem. Here, 3D pseudo-shape descriptors are proposed for characterising the particle shapes. The microscopic characteristics are recorded using a computer-based image analysis system to assess particle shape. The particle shapes are based on the complete coverage by a set of images of the particle projections in three mutually perpendicular directions. The circularity of particle projections in each plane was measured in turn and found to be suitable for particle shape estimation. Analogues of the resulting 3D pseudo-shapes are constructed for the purposes of computer simulation of non-spherical particulate assemblies. Preliminary results of the simulation work are illustrated.