During the latest DIS workshops, the addition of a Terrain Manager or Environment Manager to DIS brought out understandable differences of opinion. Options discussed have covered the responsibilities of the Terrain and/or Environment Manager, its effect on the entities, and how entities keep track of the changing environment while considering whether any fundamental goals of the DIS paradigm such as "No central computer for event scheduling or conflict resolution" are violated. However, providing a consistent and dynamic environment in DIS exercises requires more than single environment management module, whether it be per network or per node. Instead, modifications to the simulation support architecture as a whole, must be contemplated.

Issues such as network bandwidth, CPU performance, and scalability must be considered by a system architecture that supports dynamic environments in a distributed interactive simulation. To address this need, several architectures are presented which could support dynamic entity/environment interaction. As each architecture is discussed, results and measurements made from prototype software are presented to point out strengths and weaknesses. IST demonstrated networked Dynamic Terrain (DT) capability using the most recent architecture at the I/ITSEC'93 conference. The architecture supported changes to the terrain profile, an extended DIS protocol, and provided a consistent way to manage changes made by entities.