This study presents a metamodel-driven optimization of load-adaptive Voronoi lattices for cranial implants using field-based control of geometric parameters. A metamodel was established by varying cell size in loaded and beam diameter in unloaded regions, enabling stiffness predictions with 1.2 % accuracy and a coefficient of prognosis of 0.86. Sensitivity analyses showed a strong influence of beam diameter (r = 0.94) and a moderate effect of cell size (r = –0.46) on the lattice stiffness. The optimized lattice achieved bone-like stiffness with a safety factor of 2.5 under physiological loads, demonstrating the efficacy of Voronoi-based, field-controlled design as design element in implants.