Hi everyone, I've been trying to figure out how OpenSim performs its Joint Reaction Analysis when muscles are wrapped around objects. Specifically, given a muscle force, how does OpenSim determine the XYZ contributions of that muscle force to a joint when using Joint Reaction Analysis tool? This see...

Hi Bryce, Thank you so much for your reply! I did realize shortly after posting, and your reply confirmed it exactly for me, that the coordinates in the bone geometry file are all defined within it's own local coordinate system -- I was thrown off because some of the bone files don't have an actual ...

Hi everyone, Is there a way to transform (translate and rotate) the local coordinate system for bones/segments? I want to change some muscle attachment sites, but the muscle data I currently have is defined in a different reference system than the model I am using. Specifically, I am interested in c...

Hi James, Sorry, thought I had attached the file with the last post. I can't seem to be able to attach any files/zips with the post, but I included below the contents of the input file I used as a code (this was the only file I used as an input - to prescribe the model both a motion and an activatio...

Hi everyone, I'm just beginning to get into OpenSim 3.3 and went through the tutorials/examples, but have been running into some issues with estimating muscle forces while manually prescribing the model some input activations. I am interested in estimating muscle forces (both active and passive) in ...