An apparatus is provided for implementation of a mid-surface modeler including a receiver, selector, clusterer and mid-surface constructor. The receiver is to receive a solid model of a structural product composed of structural components, with the solid model representing the components by a collection of geometry. The selector is to select a group of geometry from the geometry in the solid model, with the group of geometry having approximately the same shape, and being perpendicular to an axis of a local coordinate system. The clusterer is to cluster geometry of the group of geometry into one or more clusters of geometry based on a relationship between the geometry, with each cluster of the cluster(s) representing a component of the component(s). And the mid-surface constructor is to construct a mid-surface model of the product, including computation of respective one or more mid-surfaces for the cluster(s).