A unified model for representing objects with physical properties, semantics and functionality in virtual environments

World representation is a crucial aspect of any design and development effort in the field of Virtual Environments today. Approaches presented so far don't seem to address all relevant needs. In this paper, we propose a model for the representation of physical properties, functionality and semantics of objects in virtual environments. Our proposed model aims to be uniform, pragmatic, systematic and extendible. We demonstrate practical usage of the proposed model through a complete example. Also, we briefly describe two case studies of fully-implemented virtual environment applications that encompass the proposed model in the context of diverse virtual agent interactions.