Advanced Visualization of DEVS and Cell-DEVS Models in CD++/Maya Ayesha Khan Gabriel A. Wainer Department of Systems and Computer Engineering Carleton University 1125 Colonel By Drive Ottawa, Ontario, K1S 5B6, Canada amkhan2@connect.carleton.ca, gwainer@sce.carleton.ca ABSTRACT: CD++ is a modeling and simulation tool that was created to study complex systems by using a discrete- event cell-based approach. It was successfully employed to define a variety of models for complex applications using a cell-based approach. In order to improve model validation and analysis, we introduced a 3D visualization engine, which is based on the Maya 3D visualization tool and its scripting language. The application allows virtual worlds to be developed using the Maya visualization environment, and permits interaction with DEVS models built in CD++. The result is an enhanced simulation environment, which permits improved experimentation. We discuss how these two applications interact, and how models defined earlier in CD++ can interoperate with advanced visualizations built based on Maya 3D models. 1. Introduction At present, a large number of modeling and simulation techniques and tools have been developed to deal with complex systems. A technique that is gaining popularity in recent years is called Discrete Event Systems Specification (DEVS) [1], a framework for the construction of discrete-event hierarchical modular models, allowing for model reusing. In DEVS, basic models (atomic) are specified as black boxes, and they can be integrated together forming a hierarchical structural model (coupled). Cell-DEVS [2] extended the DEVS formalism allowing the simulation of discrete- event cellular models. The approach extends traditional Cellular Automata (CA) [3] defining each cell in a cell space as a DEVS atomic model and the space as a DEVS coupled model, including a flexible way of defining the timing of each cell. We developed an environment, called CD++ [4], which implements DEVS and Cell-DEVS theories. CD++ enabled us to solve successfully a variety of complex problems [5, 6, 7]. CD++ also provides remote access to a high performance DEVS simulation server. The end user tools were organized as a simulation client applied to the CD++ simulator. Using these facilities, the users can now develop and test their models in local workstations, and submit them to be simulated in a remote CD++ server executing in a high performance platform. Then, they can receive, visualize and analyze the results on a local computer, improving model definition and execution. Visualization tools are crucial in helping to understand better the behavior of these systems. CD++ was recently provided with facilities for 2D and 3D visualization using VRML and Java [8]. This 3D GUI enables sophisticated visualization of Cell-DEVS models only, and DEVS models can only be visualized in 3D; thus we have focused on new extensions that can be applied to both DEVS and Cell-DEVS. The interface here presented is based on the Maya modeling environment [9]. We will show how advanced DEVS models can be visualized using Maya facilities, giving a few examples of application, which permit discussing interoperability of a M&S tool based on DEVS and an advanced generic visualization environment like Maya. Figure 1: CD++ server architecture 2. DEVS, Cell-DEVS and CD++ A real system modeled with DEVS is described as a composite of sub-models, each of them being behavioral