Relations between morphological characteristics and effective permeability in nanocomposite systems are here considered in details, both analyzing modeling results for simple systems as obtained in different past attempts and extending the applicability of the latter to more realistic configurations. In this perspective, the same mathematical tool and modeling approach used in a previous paper for the analysis of simple 2-D ordered systems [J. Membr. Sci. 327 (2009) 208-215] are here extended in several different respects. Predictions from numerical simulations for 3-D ordered and random systems, both for the case of low and high concentration of inclusions, are compared with results from previous works and with correlations offered by empirical approaches. A new model is finally proposed for the prediction of permeability in random systems which proves to be reliable in a rather large range of geometrical and morphological configuration. (C) 2011 Elsevier B.V. All rights reserved.