A trivariate interpolation technique, the modified Shepard's method, was applied for the first time to explain and predict various properties of macroporous polymers from the Hansen solubility parameters of the porogens employed for polymerization. Highly crosslinked polymers and copolymers were prepared from ethylene glycol dimethacrylate and methacrylic acid by free-radical polymerization with 30 different porogenic solvents. Instead of the spherical model used by Hansen, detailed three-dimensional maps were computed to represent the measured properties in a delta(d)-delta(p)-delta(h), diagram (where delta(d), 6(p), and 6(h), are the Hansen solubility parameters according to the three types of bonding forces: dispersion, polar, and hydrogen-bonding, respectively). This method was able to detect unapparent correlations between the different polymer properties, thus providing a better understanding of the pore-formation process. An important finding was the crucial role of the initiator solubility and its partitioning between the solution and the polymer surface, which proved to be key factors for the explanation of many contradictory solvent effects. (C) 2007 Wiley Periodicals, Inc.