Calculation of forces

[Leonie Müller]

To whom it may concern

I use Opencap as part of my baccalaureate thesis and have recorded various sessions. In my work, I calculated the forces that act on our joints during different movements. Now I would like to have a literature value with the 3D modeling, with which I can then check my own calculations. This aspect is particularly interesting in my work. My problem: I'm unsure how to get from my session to force calculation in Opencap. I'm sorry if this question has already been asked in the forum and I missed it. In this context, could you recommend any other interesting charts or values that I could include in my work? Because the kinematic diagrams with angle and time do not answer my question of forces.

Yours faithfully
Leonie Mueller

[Matt Petrucci]

Hi Leonie,

OpenCap only provides kinematics out of the box. If you want to calculate forces, you will need run dynamic simulations. We have provided code here to get started: https://github.com/stanfordnmbl/opencap ... inetics.py

You can also watch the tutorial that has a bit more information about how to run these simulations here: https://www.youtube.com/watch?v=7Xk8-K7A3Zk

Hope this helps,
Matt

[Leonie Müller]

Hello Matt,
Thank you very much for your prompt feedback. I tried the whole thing as shown in the video - i.e. with the program Spyder and anaconda prompt. The problem with this is that the "utilsOpenSimAD" module somehow does not exist. I've already downloaded opensim. May you help me quickly? The example file is actually great for my purposes, because I mainly have basic movements like squat or jump with landing in my session and now I want to create a dynamic simulation for it. Thank you for your prompt reply!

Kind regards,
Leonie

[Antoine Falisse]

Hey, utilsOpenSimAD is part of opencap-processing: https://github.com/stanfordnmbl/opencap ... enSimAD.py. It is not part of OpenSim itself.

Make sure you follow all the instructions here to get started: https://github.com/stanfordnmbl/opencap ... quirements

Best,
Antoine