novel compositions and methods are provided for use in the stepwise , layer by layer fabrication of three - dimensional objects , in which a build material contains a metal having a covalent bond to a non - metal , and the layers are processed to produce the three - dimensional object at least in part through a chemical reaction which alters the covalent bond of the metal . in a first aspect of the invention the build material includes a metal that is covalently bound to a polymeric precursor . in another aspect of the invention , the build material includes a metal , me , that is covalently bound to a first ligand , l 1 . following deposition of the build material , the first ligand undergoes a redox reaction with a second ligand , l 2 , thereby breaking the covalent bond of the metal . in more preferred embodiments of this class , l 1 and l 2 react to form a gas , and the metal reacts to form an oxide such as meso x , meno x , meco x and so forth . in yet another aspect of the invention , multiple build materials are employed to provide non - uniformities such as electrical , thermal , and magnetic conduction paths , structural supports , chemical and wear resistant areas , and so forth .