This ebook represents the best papers from the Twenty First Annual International Solid Freeform Fabrication Symposium – An Additive Manufacturing Conference, held August 9-11, 2010 in Austin TX (USA). The materials representation is diverse, including metals, intermetallics, glass, and polymers. There are advances in materials, processes and hardware. The authors are respected international researchers in additive manufacturing, and these articles were judged among the best 10 percent of the papers submitted to the SFF Symposium Proceedings volume.