Your opinion on OpenSim

[Antonio Parziale]

Dear all,
these are my first step in the fields of software tool for musculoskeletal modeling. I need to use them for modeling and simulating an upper limb and its "control stage" in an handwriting generation task.
I read an article in whitch the author wrote:

OpenSim shares many of the features and algorithms in SIMM but it has no tools for building new musculoskeletal models and its tools for editing existing models are very limited. The users of OpenSim have therefore been advised to purchase and use the tools in SIMM to build and edit their musculoskeletal models.

Is it right? Are you agree with the author?
I would like to use the model of muscle proposed by Loeb (virtual muscle). Do you think is it difficult to implement it using OpenSim?
I see that MSMS is another software tool that implements this kind of muscle model but I want to be sure that I'm doing the right choice before starting.

Thank you for your help!
Antonio

[Jennifer Hicks]

Good questions. OpenSim has always had the ability to build and edit models via editing the xml tags that define model components (like muscles and body segments). Here is an example that shows this process:
http://simtk-confluence.stanford.edu:80 ... el+Editing

As of OpenSim 3.0 (a version of the software that came out after the cited article was published), the graphical user interface also includes a property editor that allows you to change the properties of components of a model (e.g., changing the tendon slack length of a muscle):
http://simtk-confluence.stanford.edu:80 ... el+Editing

You can also build models programmaticaly in Matlab. For example, see this recent webinar and associated example:
http://simtk-confluence.stanford.edu:80 ... nuary+2014

OpenSim does include computational muscle models. In your case, it would probably be easiest to start with an existing upper extremity model, and add any additional muscles you want by adding the appropriate xml tags (as in the first example I linked to above). You could then edit the muscles and their geometry in the OpenSim GUI.

Also, here is a list of available OpenSim models developed by our team, as well as other researchers around the world. One of these might be helpful to get started:
http://simtk-confluence.stanford.edu:80 ... tal+Models

Hope this helps!
Jen
OpenSim R&D Manager