System acceptance is strongly related to its usability. It is important that the usability is carefully designed during the system design steps and later propagated to the interface. This care avoids reworking the interface design of an application in the future because of its usability. However, we did not find works that specifically addresses the modeling of interfaces in conjunction with usability. The Interaction Flow Modeling Language (IFML) is a proposal that supports the modeling of the interface. This work investigates the following research question: "usability in IFML models is perceived and propagated to the final interface?" In order to answer this research question, we performed an empirical study to evaluate how usability is perceived by participants through IFML models and if usability is propagated to an interface prototype. The study showed that not all aspects of usability are easily perceived and propagated in the interface through IFML models.