The study of design cognitive activity began in the 70s under the influence of psychology and ergonomics. Since then, the design process has undergone many changes with the advent of technology. This paper will notably present you to one of them: the Spatial Augmented Reality (SAR). The study conducted with this technology will focus on multimodal analysis in co-design meetings were we have compared two co-design sessions. We notice that the design activity is unchanged by the introduction of such a technology but could encourage interactions from clients who are usually less invested.