Hi Margaret, you can add the forces by adding the following in your .osim file of your model: <CoordinateLimitForce name="PP_LimitForce"> <coordinate>PP</coordinate> <upper_stiffness>0.1</upper_stiffness> <upper_limit>90</upper_limit> <lower_stiffness>0.1</lower_stiffness> <lower_limit>-5</lower_lim...

Thanks for the replies so far! But as far as i can see only the Millard2012EquilibriumMuscle model and some of its variations are described in http://simtk-confluence.stanford.edu:8080/display/OpenSim/Millard+2012+Muscle+Models The Millard acceleration model seems to use a different approach than th...

Hello everybody, i am currently in the progress of writing my masters thesis and have been using the Millard2012Acceleration model for some CMC- and forward dynamics calculations. So i'm currently looking for some information on how exactly the muslce model works and what the differences to other mo...

As far as i know you can simply open the .osim file in your favourite text editor and do a search and replace. Replace "Schutte1993Muscle_deprecated" with "Thelen2003Muscle" or the muscle model you want to use. When you open the file in OpenSim it will set the Thelen specific parameters to default v...

Hi, if i understand you correctly you want to convert your scanned data into an OpenSim model. OpenSim uses the .vtp file format for the visualisation of bodies. I have never done this before but there should be a way to convert your .k and .surf data into the .vtp format. For .vtp editing i used Pa...

Hi, sounds to me like the tendon-slack-length of the muscles is either too high (no force is applied to the body at all and the body swings under the influence of gravity) or too low (both muscles pull too strong passively on the body and OpenSim struggles to find an equilibrium). You can try to the...

Hi, i am currently trying to perform some static optimization calculations on an updated version of the wrist model i am working on at the moment. I generated a simple finger movement motion in a text editor which performs an extension of the index finger in the MCP joint: time 2_MCP_flex pro_sup 0 ...

Hi Ayman, thank you for your reply. 1) I don't expect the joints to reach their limits. I've already added some coordinate limit forces earlier but they seemed to really slow down the calculations so i deactivated them for now. Besides i'm not sure if they are really needed to get the desired behavi...

There is probably an easier way to do it, but you could try to first create the ArrayDouble and then edit the values of the array via the set(index, value) method (e.g. unitInertia.set(3, 0.0)).

Regards,
Yannik

Hello, i'm currently trying to update the wrist model that comes with OpenSim, so it can be used for inverse dynamics / static optimization calculations. I've already added the missing joints and mass/inertia parameters to the model but now i have troubles finding the right muscle parameters. First ...