It is known that even if process information at macroscale is fully accessible and properly utilized in manufacturing, product and process performance may be still not sufficiently assured. This may be due to the influence of phenomena at finer scales, which are normally not measurable and thus unknown in operation. Besides, even if such information is available, how to integrate it across scales is yet to be discovered. In this work, an integrated process and product analysis methodology is developed via a multiscale approach. This methodology can provide deep understanding of various interrelationships across multiple scales of length and time, which could be essential for substantial improvement of product and process performance. The methodology is successfully applied to the analysis of the paint spray operation in automotive surface coating, with the extension of the analysis from the macroscale of 10(-2)-10(1) m and 10(0)-10(2) s to the meso-macroscale of 10(-6)-10(1) m and 10(-5)-10(2) S. Model-based simulation reveals various new opportunities for simultaneous improvement of coating quality, energy and material efficiencies, and environmental cleanness. (C) 2007 American Institute of Chemical Engineers.