We are pleased to announce OpenSim 4.1 <https://simtk.org/frs/?group_id=91>. The new software enables users to read in inertial measurement unit (IMU) data and compute inverse kinematics based on IMU orientations. This workflow is called OpenSense. This is an exciting initial step towards supporting biomechanical analyses with IMUs in OpenSim. For this release, the user is primarily responsible for ensuring proper calibration and registration of the sensors to an appropriate OpenSim model. In the future, we will add more advanced algorithms for calibration, registration, and drift correction. You can read more about these new capabilities and try an example: OpenSense - Kinematics with IMU Data <https://simtk-confluence.stanford.edu/display/OpenSim/OpenSense+-+Kinematics+with+IMU+Data> . We have also fixed several bugs and improved the user experience. Read more and learn how to upgrade <https://simtk-confluence.stanford.edu/pages/viewpage.action?pageId=36439186> . Download OpenSim 4.1 <https://simtk.org/frs/?group_id=91>. -- *Jennifer Hicks, Ph.D.* Director of Data Science | Mobilize Center <http://mobilize.stanford.edu> Associate Director | NCSRR <http://www.stanford.edu/group/opensim/about/index.html> R&D Manager | OpenSim <http://opensim.stanford.edu/> Stanford University 650-498-4403 | jenhicks@stanford.edu