摘要：This research applied an open structure of generative design in order to provide parametric sliders for users to adjust a digital model under the designer"s plan. Moreover, the design outcome can be printed immediately using 3D printing technology, to experiment with users" preferences and see the effects of generative design in modifying pattern, regular/irregular and detail transformations on a product. Three types of feature modification on iPhone4 case were chosen as simulations by three design experts. Five experienced and five young designers were asked to manipulate a digital generative design model as they want. Then 2D rendering images and 3D printed mockups were presented for subjects to compare with their original design. The result demonstrated that experienced and young designers both can recognized their work in 3D print mockups. Experienced designers can use the limited tool to make distinct outcomes for more satisfaction form tan subjects. Young designers expected to obtain 3D printed mockup to help their design decision in design process.