The foundations have been laid out for estimating design parameters in ordered packing materials based on fluid mechanics and mass transfer without any adjustable parameters. Design parameters for heat- and mass-transfer processes over ordered packing materials can be estimated using the knowledge developed on the study of flow patterns and velocity parameters for thin viscous films over complex surfaces. Velocity profiles can be integrated to calculate liquid holdup and interfacial areas. The effect of the size of the structured packing as well as liquid properties on these parameters was explored. Flow visualization experiments were performed to determine the path followed by tracer particles in the liquid film flowing over the inclined corrugations of a hacking element. Contact times for tracer particles to travel one wave of the packing element can be evaluated using the packing geometry and the path followed by the particles. Mass-transfer coefficients for the liquid phase were estimated using a penetration theory model. These parameters were used to predict height of a transfer unit (HTU) and height equivalent to a theoretical plate (HETP) for typical commercial packing materials and compared with existing experimental data. The results shown here conform to a basic model of flow and mass transfer in ordered packings that can be used for research and design purposes.