1. A method of selecting a profile model and selecting parameters of the profile model for use in optical metrology of structures in a wafer, the method comprising: a) selecting a template associated with a wafer structure from a plurality of templates, the template having one or more parameters based on: characteristics of process, and profile modeling attributes for use in optical metrology of a structure in a wafer; and b) generating a profile model characterizing the wafer structure based on the one or more parameters of the selected template.