OpenSim version 1.8 is now available. OpenSim is freely available to the biomechanics research community and enables modeling and simulation of human and animal movement, including inverse dynamics analysis and forward dynamic simulation. The new version allows general purpose inverse dynamics and static optimization to estimate muscle forces. The software, models, tutorials, and example simulations are available at the project website: https://simtk.org/home/opensim. There are now over 2000 OpenSim users who are beginning to contribute models, simulations, and new capabilities to the software. Some new features in version 1.8 include the ability to: (i) build plug-ins that extend the capabilities of OpenSim, (ii) graphically define and edit mocap marker positions, (iii) define complex joints with constraints. If you are currently using an earlier version, I would encourage you to upgrade. Best wishes - Scott -- Scott L. Delp, Ph.D. Charles Lee Powell Professor Stanford University, Schools of Medicine & Engineering Clark Center, Room S-321 318 Campus Drive, Stanford CA 94305-5444 voice: 650.723.1230 http://www.stanford.edu/group/nmbl/ http://bioengineering.stanford.edu/