An information model is presented that supports sharing of design definition data between the designs of completely configured variants within a product family. Design data sharing is supported across many levels of a design’s product structure hierarchy: A change in one subassembly component does not force the whole subassembly to be duplicated. This is achieved for completely configured models and does not require the use of effectivity or any other filtering mechanism. The key is recognizing a product structure architecture that acts as a template for product variants, maximizing data sharing between them. This approach is applied to many distinct product structure abstractions, including the geometric design and the logical systems design of a product. It is extended to include secondary product structure data such as interface connection points (e.g., ports) and connectivity information, which may involve connections between ports or the mapping from the logical systems design to the geometric design that implements it. This model achieves data scalability for hierarchical product structures, meaning that when adding a new product variant, the amount of new data that must be added is proportional to the amount of design change required for the new variant times the logarithm of the total system size (this logarithm is taken to the base of the branching factor of the product structure tree).