A method for creating or forming a functionally graded 3D ordered open-cellular microstructure, and a functionally graded 3D ordered open-cellular microstructure. In one embodiment, the functionally-graded three-dimensional ordered open-cellular microstructure includes a first three-dimensional interconnected pattern of polymer waveguides having a first three-dimensional pattern; a second three-dimensional interconnected pattern of polymer waveguides having a second three-dimensional pattern differing from the first three-dimensional pattern; and an interface connected with the first three-dimensional interconnected pattern of polymer waveguides and the second three-dimensional interconnected pattern of polymer waveguides. Here, the term “functionally graded” refers to a spatial variation in the physical microstructure—and thus the properties—through the thickness of the material.