1. A computer aided design (CAD) system, comprising: interface means configured to receive input defining at least a portion of an engineered structure; processing means configured to modify data that represents at least a portion of the defined engineered structure, including the engineered structure's material composition, wherein: the data structurally comprises a plurality of nodes hierarchically arranged in a shared, regularly-subdivided tree arrangement including a plurality of leaf nodes; each of the plurality of nodes is associated with a spatial subdivision of another node associated with a higher hierarchical level; and each of the plurality of leaf nodes is associated with one of a plurality of cube data structures each comprising a digital representation of a cubical spatial subdivision of the engineered structure and representing the material composition of the spatial subdivision of the engineered structure corresponding to the leaf node; a library of component cells that are selectable via the interface means; and means for storing the data and the library; wherein the material composition is selected from a list consisting of: a semiconductor material, a ceramic, an oxide material, and a metal.