(en) As mobile devices are constantly evolving, new requirements are emerging regarding their screens: bigger displaying surfaces, enriched user interactions, enhanced robustness, adaptability,... many requirements foldable screens would provide a way to fulfill. For example, they would allow to enjoy bigger displaying surfaces by simply using unfold operations, preserving the small dimensions these devices require in mobile situations while maximizing the display surface in fixed situations. In order to test and evaluate such device capabilities, prototypes must be built. However physical prototypes elaboration remains a complex, time consuming and expensive process due to the multiple new technologies involved. This thesis addresses this issue by allowing the creation of virtual rather that physical prototypes. It is achieved by developing UIFolder, a software tool allowing the definition of the prototype physical structure, folding capabilities and user interactions techniques. An extension of the Yoshizawa-Randlett origami notation system is proposed to graphically represents the prototype characteristics. Then the prototype definition is rendered in a virtual world allowing users to manipulate the virtual prototype. Thus this 3D prototype representation can be used to test and evaluate its usage.