Physics Engine Benchmarking in Three-Dimensional Virtual World Simulation

The U.S. Army is continuously looking for novel and innovative methods and technology to enhance operational and tactical simulation-based training (SBT) for its soldiers. Through the Military OpenSimulator Enterprise Strategy (MOSES) project, the U.S. Army Research Laboratory is identifying critical software features that will improve the next generation of military simulation’s training effectiveness. At present, MOSES is investigating methods to increase the number of simultaneous soldiers that can train in a three-dimensional (3D), virtual world simulator. The current limitation of simultaneous trainees in a high-fidelity environment is approximately 16-44 soldiers, representing the platoon echelon in the U.S. Army. This limitation is unfortunate as the Army requires the next generation of SBTs to support training at the company echelon of (100-200) soldiers. The presented work investigated a common limiting factor in virtual world simulations, the physics engine. We compared the physical load limits of three physics engines; Open Dynamics Engine (ODE), Bullet, and PhysX. These engines were studied because they are common in video games, special effects for television and film, and 3D simulations. More specifically, ODE was the first physics engine implemented for the virtual world simulator, OpenSimulator (OpenSim). BulletSim is an award-winning and industry-recognized engine that is the current default OpenSim physics engine using the BulletSim wrapper. PhysX is the latest real-time physics engine from Nvidia that has been recently integrated into OpenSim. With this study, other simulation users, developers, and administrators gain a quantifiable method to compare physics capabilities among computer-based systems.