The objective of this paper is to provide a discursive platform for the broad spectrum of practitioners and researchers concerned with packing characteristics of rock particulates. The paper focuses on void porosity prediction in gravity-dominated packing, drawing on the breadth of disciplines that have addressed this problem. The different approaches to accommodating size distribution, shape, looseness of assembly and absolute size are variously explained or touched upon. The main part of the paper is a selective summary of recent contributions to semianalytical and empirical prediction models. An attempt to compare several porosity prediction models for a range of uniformity in the size distribution is reported. The reasons for differences are discussed. This leads to a consideration of the vital role that numerical modelling of particulate behaviour can play and a number of recent research developments in particle pack simulation are highlighted. The main problems associated with the numerical modelling of rock particulates are found to be those related to the modelling of the interaction between angular irregular particles with real shapes. 3D visualisation results are illustrated from a space filling tetrahedron assembly model and a dynamic interaction model for real-shaped particles under development by the authors, The paper concludes that better approaches for characterising the shapes of populations of rock particulates will be required to service the numerical models of the future.