As is now widely recognized, Additive Manufacturing offers many potential advantages to both users and industry, with one of the principal benefits being in the extended levels of design freedom and complexity that can be incorporated into a component. For single material additive manufacturing – most notably the powder bed fusion techniques, which are of particular relevance and interest to industry today – we are beginning to see examples emerging that incorporate complex lattice structures or components that involve a degree of topology optimization or parts consolidation in their design. Though many of these emerging examples are impressive, by their single material nature, they also are limited to being used as “passive” components that require integration into a larger system in order to impart functionality beyond the mainly structural. However, taking the concept of design freedom beyond the geometrical domain to one where multiple materials are simultaneously deposited opens up the potential for the creation of functionalized, “active” devices “printed” in one build operation. However, though simple in concept, this discrete deposition of dissimilar materials throughout the volume of a part creates significant technical challenges, particularly in the deposition of useful materials.