Fig. 4From: Review of heterogeneous material objects modeling in additive manufacturinga Prototypes fabricated with a hierarchical representation for unidirectional material gradient [45]. b Prototypes fabricated with non-manifold heterogeneous cells [46]. c Adaptive meshing results of 2D heterogeneous objects using material quadtree based on different thresholds [47]. d Heterogeneous feature tree structure processes objects with complex material gradient functions [48]Back to article page