Thanks Tim. Is that the same one you gave me at the Jamboree?

Ajay Seth, a member of the OpenSim team, has a plugin for this. I think it is a modified muscle that doesn't have activation dynamics.

So, I have done this exact thing. I've written Matlab code to extract BodyKinematics analysis data and transform muscle points into the global frame.

I would like to model a torsional spring: a generalized torque applied to knee_angle with a value that depends on knee_angle.

<t>Hi David,<br/> <br/> Yup. That was me in front of you. I agree it would be nice to have an analysis plugin that calculate the resultant moments and forces (due to muscles) acting on each body center of mass expressed in the global reference frame.<br/> <br/> What do you think Ayman? or any other ...

<t>Ok, so here is a proposed solution I have found. <br/> <br/> 1. Use BodyKinematics analysis to determine the location and orientation of the body COM (in global coordinates).<br/> <br/> 2. From this, you can determine where the body origin is in global.<br/> <br/> 3. You know where the muscle poi...

<t>Hello,<br/> <br/> I would like to get the force and moments acting on a body due to muscles. I know you can get muscle moments acting at generalized coordinates and muscle forces using an analysis, but I'm not sure how to break down this force into x,y,and z components. Also, I'm not sure how to ...

Hello,

I found an actuator file named TorsionalSpring.h. How can I include this in my model? I'm not sure how to use it/call it.

Thanks,

Anne

Hello,

So, I understand that you can use EMG data. However, just given EMG data, how can I use OpenSim to calculate initial states (like muscle fiber lengths)?

Thanks,

Anne

<t>A note on use from Matt: You need to have kinematics AND actuator forces (like all muscle forces and and any reserve/residual actuators your model has). these can come from CMC or Static Optimization. supply those and JointReactions calculates the forces and moments required at each joint to make...