Topology optimization creates an organic geometry flowing material to where it is needed and eroding where it is not efficient. This technology is ideally suited to the limited manufacturing constraints that 3D printing offers. 3D printed parts by virtue of their layer by layer additive manufacturing approach have complex material properties. These properties are similar to wood where there is a stiff direction (with the grain) and a weak direction (across the grain). To gain the highest performance in 3D printed parts these material properties must be considered in the design process.