The OnDemand project aims to develop sustainable and customized eyeglass frames produced through additive manufacturing using biodegradable biomaterials, promoting the replacement of conventional plastics and the circular economy. Polymer matrices of PLA, PHA, and PBS, natural reinforcements such as Luffa cylindrica, cork, and wood, as well as additives, were studied using chemical, morphological, and thermal characterization techniques. The results made it possible to identify the composition of the materials and evaluate the compatibility between the matrices and the natural reinforcements. The PHA/PBS combination stood out for its superior thermal performance and dimensional stability, proving to be the most promising alternative for the development of biodegradable and customized eyeglass frames.