The Reference Model of Gunter et al., 2000, provides a framework for describing and analyzing key software engineering artifacts and their properties. In this paper we propose a reification of this framework in which behaviour is explicitly trace-based. We find that this benefits the formalism in adding structure in ways which are meaningful and practical from an engineering viewpoint. In particular, we develop notions of points of introduction and reachability in the new framework, and show how they strengthen the properties of the Reference Model.