The paper describes the use of interactive Virtual Prototypes (iVP) for the specification of consumer products and for the evaluation of the perceived quality of the product already in its conceptual form. iVPs are based on multimodal interaction including force-feedback and sound in addition to 3D stereoscopic visualization. The fidelity of the prototypes has been evaluated in comparison with the corresponding real products, when used for performing the same tests. Differently from the traditional use of Virtual Prototypes, which aims at evaluating the product design, we have used iVPs for the interaction design of a new product, i.e. it has been used as a means to define the design parameters used for the specification of a new product.