Identifying and reducing critical lag in finite element simulations

Interactive, immersive virtual environments allow observers to move freely about computer-generated 3D objects and to explore new environments. The e ectiveness of these environments depends on the graphics used to model reality and the endto-end lag time (i.e., the delay between a user's action and the display of the result of that action). In this paper we focus on the latter issue, which has been found to be as important as frame rate for interactive displays. In particular, we analyze the components of lag time resulting from executing a nite element simulation on a multiprocessor system located in Argonne, Illinois, connected via ATM to an interactive visualization display located in San Diego, California. The primary application involves the analysis of a disk brake system that was demonstrated at the Supercomputing 1995 conference as part of the Information Wide Area Year (I-WAY) project, which entailed the interconnection of various supercomputing centers via a high-bandwidth, limitedaccess ATM network. The results of the study indicate that the critical component of lag is the simulation time. We discuss the use of network of supercomputers for reducing this time. 2