This paper focuses on modelling perception and vague concepts in the context of multiagent Bgi (Beliefs, Goals and Intentions) systems. The starting point is the multimodal formalization of such systems. Then we make a shift from Kripke structures to similarity structures, allowing us to model perception and vagueness in an uniform way, “compatible” with the multimodal approach. As a result we introduce and discuss approximate B gi systems, which can also be viewed as a way to implement multimodal specifications of Bgi systems in the context of perception.