The OpenSim team at Stanford is excited to announce the release of OpenSim 2.4, a robust and flexible software package for modeling and simulation of the musculoskeletal system. This release includes improvements to functionality, usability, and visualization that will benefit both new users and experts. We encourage you to download<https://simtk.org/project/xml/downloads.xml?group_id=91> the software and review the full list of new features<https://simtk.org/frs/download.php?file_id=2991> . The software has undergone extensive internal unit and system testing as well as external beta testing with walking, running, and upper extremity motion. In addition, we’ve verified that the results of Computed Muscle Control now match or exceed the quality of those achieved in OpenSim version 1.9.1. Some of the new features in version 2.4 include faster and more robust tools for Inverse Dynamics and Inverse Kinematics, new visualization tools, enhanced access for API users, several usability improvements, and several features to help verify your simulation results. OpenSim 2.4 also has tools to convert old model and setup files to the latest formats. We have fixed several bugs and expanded the documentation. The user’s guide has a chapter on conducting an induced acceleration analysis, which is a faster alternative to a perturbation analysis, and a chapter on getting started as an OpenSim API user. If you haven’t yet tried OpenSim or you are using an earlier vision, we encourage you to give 2.4 a spin. In addition to the OpenSim 2.4 software download <https://simtk.org/project/xml/downloads.xml?group_id=91>, we've provided a full list of the software’s new features and bug fixes<https://simtk.org/frs/download.php?file_id=2991>, general notes on upgrading <https://simtk.org/frs/download.php?file_id=2993>, and upgrade details for API users<https://simtk.org/frs/download.php?file_id=2992> . You can find out more about the OpenSim project at http://opensim.stanford.edu. Best wishes, Jen Hicks -- --------------------------------- Jennifer L. Hicks, Ph.D. OpenSim Project Manager Stanford University jenhicks@stanford.edu 650-498-4403 http://opensim.stanford.edu ---------------------------------