In event-driven design processes, a digital mock-up is made of entities which are more than 3D, passive, virtual objects; they may be seen as part of a society of agents whose behavior emerges from their mutual interaction. This paper proposes the concept of Extended Constraint Graphs with bi-directional reactivity and one-way actions to represent reactivity and pro-activeness in a society of distributed design agents. Also, while the majority of CORBA applications in CAD systems uses static invocations, this paper presents an original approach to deal with the necessarily dynamic nature of event-driven design processes through the use of the interpreted language Lua with a CORBA binding called LuaOrb. Moreover, the use of ACIS as a Geometry Bus is presented in the context of the CORBA dynamic invocation interface.