Virtual vs Physical: an experimental study to improve shape perception

Product designers, in order to create value, need to enrich their understanding of users products experience and the whole set of activities involved in it. Human-Centered Design (HCD) regards with the development of design principles to support product features definition answering to physical, psychological, social and cultural needs of human beings. Usability tests generally allow the investigation of product performance in terms of efficiency, effectiveness and users satisfaction in order to reduce the gap between the perceived and the designed product quality. Main problems concern with the assessment of emotional usability, the identification of product features stimulating affective response and their translation into design requirements. Usability tests are generally carried out only at the end of the design cycle once a final physical prototype has been realized. As a consequence design modifications increase time to market. Instead of traditional CAD-based systems (Computer Aided Design), Virtual Reality (VR) represents new Human-Computer Interfaces that can support the multimodal interaction with virtual prototypes to perform usability tests at the early design stages. The present paper explores the potentialities of VR to support usability testing mainly focusing on emotional aspects. A protocol study is defined to analyze how sample users perceive product attributes determining affordances and synaesthesia qualities. The protocol adopts qualitative and quantitative metrics to objectify users emotional response while interacting with products. It allows correlating product attributes, in terms of materials, shape and aesthetic features combination, with user behavior and product performance. It has been applied in the field of household appliances. Two different experimental set-ups, physical and virtual, have been used to validate the protocol and highlight the main VR technologies drawbacks.