This paper introduces the concept of granular modelling as a strategy to construct human-centred virtual prototype and environment models. This approach aims at providing a granular strategy for virtual prototype models in order to allow the change from a coarse-grain description to a fine-grain one according to the level of specification desired. The granular model is built from the aggregation of several component models and their interaction models, representing the interaction between two components. Component models must include information not only about themselves but also about the environmental part related to them. This is important as environmental conditions may have different effects at different scales/levels. Additionally, it leads to a higher level of communication, only allowed through the interaction models. This implies that new different objects might be integrated only by including their component models and their required interaction. The foreseen advantage is that the human is integrated in a simple manner: a component model corresponding to a haptic interface and an interaction model relating it to the virtual product. The first step, identification and organic description, consists of establishing an interaction graph from the hierarchical structure of the virtual product and all the objects that will be present in its future environment. Subsequently, the component and interactions models are constructed. The model is expected to be implemented into a multi-agent system where every component model derives into a component agent.