We are pleased to announce that OpenSim 3.3 is now available for download . The release includes new examples and scripts that make it even easier for you to get started and help you evaluate the quality of your simulations. Based on your feedback, we have also enhanced OpenSim to automate more of your workflow. Some of the improvements in the release include the following: * The Static Optimization tool now has better error handling and error messages. It is also compatible with models that have passive elements, so you can now solve muscle activation problems for a more diverse set of models, even those that include springs, ligaments, and bushing elements. * We created a new example demonstrating how to understand and improve the results of a Static Optimization analysis. * The Scale tool now automatically handles the scaling of ligaments, eliminating the need for the cumbersome manual process employed by users. * We created a new script to help generate a reserve and residual actuator file for use with RRA, CMC, or Static Optimization. You will be able to set up and run these tools much more quickly, while also avoiding common pitfalls that cause the tools to fail. * We have upgraded to Simbody 3.5 , which includes support for Contact mesh files in .obj or .stl format and several new features for advanced API users, including access to the CMA-ES global optimizer. * Several bug fixes based on reports from our users. * Compatibility with Visual Studio 2013 and Visual Studio 2015 Release Candidate If you're already using version 3.2, upgrading to 3.3 will require at most minimal changes to your models, scripts, and other files. Our website includes a full list of new features and upgrade notes . --- Joy P. Ku, PhD Director, Simbios Director of Communications & Training, NCSRR Director of Communications & Engagement, Mobilize Center Stanford University (w) 650.736.8434, (f) 650.723.7461 Email: joyku@stanford.edu