Plastic is an important material in product design because it easily transforms, is very light, and has multifarious structural characteristics. Nevertheless, it gives the customer the impression of a cheap product. Therefore, decorative techniques are often applied to plastic products. Decorative techniques can improve the appearance of a plastic product while making use of its beneficial characteristics. At present, film insert molding method is predominantly used in decorating plastic products. In general, a designer creates a three-dimensional design but the film insert molding method uses a two-dimensional pattern. Thus, it is difficult to reproduce a three-dimensional design with a two-dimensional film; no study has been conducted on the reproduction of three-dimensional design using film insert molding method to-date. The objective of this study is to develop a design generation method to reproduce a three-dimensional design with a twodimensional film pattern. The effectiveness of the proposed method is experimentally validated.