Week 3: Data Processing (cont.)
March 18, 2026
Hi everyone, and welcome back to my blog! This week I continued to work on data processing, which is one of the main parts of my project.
Last week I started writing the code to convert my Witmotion sensor data into a format that the OpenSim software can use (read my last blog for more details!). However, there were still some minor errors in my code from last week. One problem was that my headers were incorrect. Instead of naming the sensors body parts (e.g. head, pelvis, etc), my headers were still left in the WitMotion format of WTD1_Q0, WTD10_Q0, WTD11_Q0, etc. OpenSim couldn’t recognize the sensors and wouldn’t read the file properly because of that. To combat that, I added a sensor map that mapped each sensor to a body part as shown below.
The conversion script should be good now. I was able to convert my raw Witmotion CSV data into an OpenSim-compatible .sto file, with properly formatted time columns and quaternion orientation data for each sensor. Each sensor is now labeled according to its corresponding body segment using the sensor map, which allows OpenSim to correctly interpret the motion data. (Shown below)
After fixing up the minor bugs and tweaks, I attempted to load the motion onto the model. However, I still had issues with the IMU Placer tool. Even though I loaded the motion and data into the IMU Placer, the software wasn’t letting me play the run button. I will need to investigate deeper about why that happens.
I’m aiming to finish this data processing step by next week—come back then for an update!
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Hi Michelle, it looks like you made some great progress with loading the data this week! I really like how you included a lot of visuals to guide the understanding process (especially that little figure you drew and the converted data tables). I was just wondering whether the OpenSim software has some sort of documentation that would help you in figuring out the formatting issues and how to fix the IMU Placer problem? Also, I recall you said that you’d be comparing the form of players to some professional players. Are your getting the same quaternion orientation measurements for the professional players later for comparison, and if so, how do you plan on doing that?
Hi Chloe, thanks for your comment and great questions! Regarding your first question, yes the OpenSim software does have a very detailed and comprehensive documentation that I have been referencing to a lot—from learning the tools of the software to debugging issues. Regarding your second question, I’m planning to take some high level players around the area instead of getting professional players, since that seems like a more feasible plan.
Hi Michelle!
I love seeing your problem-solving strategy and the diagram illustrating the sensors’ placements on the body. Good luck with the data processing step!
Hi Michelle,
Looks like you have made a lot of progress, being able to set-up the software for your final product! I look forward to seeing how you approach the issues in the IMU placer tool!
Hey Michelle! I loved seeing your progress visually so far on your project! It was super interesting to see how you’ve mapped out the sensors and adjust it to be compatible with OpenSim! Excited to see what’s next!