We are in the process of updating this documentation for OpenSim 4.0. Are you looking for OpenSim 3.3 documentation?



Most users should be able to upgrade to OpenSim 3.2 from OpenSim 3.0 or 3.1 without any major changes to their models or simulation workflows. A few upgrade notes for users:

1) If you are using Matlab scripting, you will need to re-run the set-up process to direct Matlab to the appropriate libraries for 3.2. We have added a configuration script (in the Scripts/Matlab folder) to make this process easier for 3.2.

2) We fixed the handling of moving path points in OpenSim, in particular the calculation of moment arms. This may affect simulation results for any models that use moving path points, including the gait models distributed with OpenSIm. The change brings the quadriceps muscle moment arms more in line with values reported in the literature.

3) We fixed bugs in the metabolic calculators (probes). These changes may have a small effect on metabolic calculations.

4) We fixed bugs in the Scale:MarkerPlacer and InverseKinematicsSolver: Coordinate Tasks are now used when computing the solution (they were previously being ignored) and their Apply flag is respected. If this changes your Scale or IK results please check your files and update accordingly (e.g., remove coordinate tasks to get the same behavior as in previous versions).

5) We moved to a single set-up file for both Scale and Inverse Kinematics in 3.2 You can continue to use old Tasks file from GUI and/or Scripts but if you save a new file from the GUI, it will absorb the Tasks into the main setup file. From then on, you should remove old Tasks file as they will be ignored and the Tasks saved in the setup file will be used instead.