<p>This study provides a theoretical investigation into the union of topology optimization (TO), additive manufacturing and composite materials for the manufacturing industry. Additionally, the added weight saving and structural performance enhancement benefits of lattice structures are examined. In this study, a single-seater chair made of both Polylactic acid (PLA) and a PLA/Wood composite material was subjected to a TO study in efforts of reducing the overall material usage and enhancing its structural performance. A static analysis was used to conduct comparative analyses to examine the behavior of TO technology to change in material properties, to highlight the superiority of computational TO when compared to design- based optimization, as well as to examine the added benefit of lattice structures. Through this study, a composite lattice structure was created in efforts of defining a unified lattice structure that provided optimal structural reinforcement of the multi-mode deforming chair. It was found that the TO technology was largely dependent on material characterization as it relates to the aggressiveness of material penalization. In addition, the composite lattice structure was highlighted for its superior weight-saving property while still maintaining competitive mechanical performance over the FCC and Diamond TPMS lattice models.</p>