A computer-implemented method and system for modeling an outer surface, such as skin. The method includes, under the control of one or more computer systems configured with executable instructions, defining a plurality of microstructures such as microstructures to be displayed in microstructure locations on a geometric model of a character or inanimate object, and generating a volumetric mesh including the plurality of microstructures. The volumetric mesh is configured to be applied to the geometric model as an outer surface (e.g., skin) covering the geometric model.