Abstract: A method and apparatus for embedding features and controlling material composition in a three-dimensional structure (130) is disclosed. The invention enables the control of material characteristics, within a structure (130) made from a plurality of materials, directly from computer renderings of solid models of the components. The method uses stereolithography and solid model computer file formats to control a multi-axis head (480) in a directed material deposition process (123). Material feedstock (126, 127) is deposited onto a pre-heated substrate (19). Depositions (15) in a layer-by-layer pattern, defined by solid models (141, 146), create a three-dimensional article having complex geometric details. Thermal management of finished solid articles (250-302), not available through conventional processing techniques, is enabled by embedded voids (152) and/or composite materials (126, 127), which include dissimilar metals (210, 216).