Mechanical metamaterials have properties that depend largely on the exhibited architecture. As such, several architected metamaterials with complex topologies that promote a stretching-dominated mode of deformation have been proposed and their fabrication was facilitated using additive manufacturing. However, most of these architected metamaterials are strut-based where several struts are joined together at certain nodes. The complexity of the node makes it susceptible to defects upon manufacturing and the sharp geometry of these nodes results in large stress concentrations. In this paper, we show that adopting a different approach in designing lattices can result in reducing the effect of stress concentration. The proposed approach is based on employing mathematically-defined surfaces with smooth transitions to create lattices. For the purpose of demonstration, metallic lattices with geometries based on the Schoen I-WP minimal surface were designed and fabricated using powder bed fusion additive manufacturing. Scanning electron microscopy was utilized to assess the quality of fabricated samples. Results showed that adopting a sheet-based approach rather than a strut-based approach can change the deformation mechanism from bending-dominated to stretching dominated without sacrificing the obtained toughness.