Additive manufacturing technologies such as 3D printing have enabled the production of complex structures and parts which find widespread use in engineering applications. Medical engineering with its need for materials with exceptional properties has taken on a key role. In addition to chemical resistance and biomedical tolerability (sterilization resistant, non-toxic and non-sensitizing), the suitability of these materials depends in particular on their mechanical properties. Biomedical applications such as, for example, bone substitutes often require mechanically optimized structures whose properties are determined not only by manufacturing conditions but also by the sizes and forms of the structures as well as the materials used. The priority of objectives in structure development include besides a reduction of implant stiffness, the achievement of bone-like mechanical characteristics and the realization of the substitute structure in a porous (micro, macro) structure or surface. While several medical technical problems with a requirement for defined mechanical properties have drawn upon titanium alloy-based applications, the use of polymers has just begun. The present paper compares the mechanical properties of 3D printed, load carrying structural elements (scaffolds) made of TiAl6V4 powder that are suited for use as bone substitute and scaffolds made of polymer materials (PEEK, ABS). Characterization was performed by assessing the functional relationship between the experimentally determined porosity and the modulus of elasticity. Special emphasis has been placed on their specific flexibility as the determining factor for deformation resistance. It offers an excellent possibility to establish a direct relationship between porosity and elastic modulus. Besides the material characteristics of the materials themselves, scaffolds with different porosities have been assessed and compared directly with the characteristics of the human bone (cortex, cancellous bone).