With the increase in the number of lightweight, high-strength and highperformance automotive parts, studies are being conducted on the application of highstrength and lightweight materials and the optimization of the thickness values of these parts. From a practical perspective, however, the indiscriminate use of highstrength and lightweight materials leads to very low mass production. Suggesting optimum design values also requires the adoption of new processes that are not practical for application in manufacturing processes. In this study, discrete material and thickness optimization (DMTO) that considers materials and thickness values for commercialization was applied.A simple model of a retractable seat frame for recreational vehicles (RVs), whose thickness and material were not fixed, was investigated. Tests were conducted to secure accurate material properties for finite element analysis (FEA), and constraints were set based on the Federal Motor Vehicle Safety Standards (FMVSS) 207 and FMVSS 210 tests. The results of DMTO were compared with those of discrete thickness optimization (DTO) to verify the validity of the design parameters.