1. A method of using a graphical user interface of a computer system to interactively generate a product definition for use in configuring a product, the method comprising: performing with the computer system: graphically displaying a parts catalog; using the computer system for: (a) selecting an element from the parts catalog, wherein the element comprises one or more parts; (b) graphically associating the selected element to create a product-to-element classification relationship; repeating (a) and (b) to complete the product definition; and using the computer system for: (c) selecting a first element from the parts catalog; (d) selecting a second element from the parts catalog; and (e) graphically associating the first and second elements selected in (c) and (d) to associate the first and second elements with one or more element-to-element relationships.