The invention relates to a process for fabricating complex mechanical shapes, and in particular to fabricating complex mechanical shapes using a pressure-assisted sintering technique to address problems relating to variations in specimen thickness and tooling, or densification gradients, by 3-D printing of a polymer model that is surrounded by and filled with sintering powder material, wherein the 3-D polymer model decomposed into a graphite interface layer and facilitates release of the cast, e.g. metal, metal-alloy, ceramic, etc., manufactured item.