OpenSim

OpenSim is open-source software for building and analyzing musculoskeletal models and simulating movement. It enables researchers and educators to create models of bones, joints, and muscles, perform forward and inverse dynamics simulations, estimate muscle forces, and optimize movement tasks. OpenSim is widely used for gait analysis, rehabilitation research, sports science, and the study of human and animal motion.

Key capabilities include constructing and editing skeletal and muscular models, importing and aligning motion capture data, and comparing simulated results with experimental measurements. It provides methods for muscle-force estimation, such as static optimization and dynamic optimization approaches, and supports forward-dynamics simulations to predict movement trajectories under specified controls. The software includes visualization, analysis tools, and scripting interfaces to automate workflows.

OpenSim supports standard workflows in biomechanics, enabling researchers to customize models, run parameter studies, and validate simulations against experimental data. It offers APIs for automation and integration, including Python and Java interfaces, facilitating batch processing and extension by developers. Models and projects are typically stored in the .osim format.

The platform runs on major operating systems, including Windows, macOS, and Linux. OpenSim is released under an open-source license, reflecting a permissive approach to community collaboration. The project is maintained by a community of researchers and developers affiliated with universities and research institutions, and it provides extensive documentation, tutorials, and user forums to support learners and professionals working with musculoskeletal simulation.