Faconti, Giorgio P.Paterno, Fabio2015-10-052015-10-0519901017-4656https://doi.org/10.2312/egtp.19901039In this paper we present the preliminary results from a work aiming to the formal specification af a model suitable for the description of interactive graphics program within the framework defined by the Reference Model for Computer Graphics Systems, actually under development within the International Organization for Standardization. The architecture defined by the Computer Graphics Reference Model, at its actual state of development, is shortly presented with particular attention paid to the concepts used in the paper. Following, the components of a basic interaction are identified and described as a set of independent communicating processes, referred to as an interactor. The relationships between interactors are described in terms of the communication between their component processes by using ECSP-like constructs.10.2312/egtp.19901039