Xsens C3D marker protocol

Hi,

I am currently trying to use my own c3d files collected from Xsens within the plug-in-gait_Simple demo folder.

My issues is c3d marker set that gets exported from Xsens. I have tried to adjust the marker protocol within Anybody to the markers that come from Xsens however there are markers that are missing within Xsens. The only way I have resolved this is by putting the file in Mokka (c3d software) and creating new markers that represent what is missing. However these configurations cannot be saved and re-applied to other files. So this becomes very time consuming for multiple files.

Is there a specific software that can translate the c3d from Xsens to what is needed in anybody? or if new configurations can be made within a software, can this be saved and applied to multiple files for export?

Or is there a simpler way of solving this problem?

Thanks,
Darius

Hi Darius,

May I ask why you are exporting c3d files from Xsens and not BVH files to use in AnyBody?

Best Regards,
Christine

Hi Christine, thank you for your reply.

I have tried the BVH model with over 10 different files, different durations, smaller motions, reducing the model to leg only analysis etc. (without making any changes to the actual model) and always receive errors that stop the analysis from completing.

I have looked through the solutions within the forum and the only option that worked with one file only was changing

Rotation2PiFixOnOff = Off;
Rotation1PiFixOnOff = Off;    

I was trying to use c3d assuming it might handle the files better.
Would you like me to send through a few BVH files to see if you can solve the errors?

Thankyou,

Darius

Hi Darius,

Yes if you could send a couple BVH files and the subjects mass/height that would be great.

Best Regards,
Christine

Hi Christine,

I’ve attached some snippets from a few files as the entire files will be quite large and long. If you could please let me know if these run correctly on your end that would be great.

Thanks,
Darius BHV files.zip (1.7 MB)

Height - 169cm
Weight - 65Kg

Hi Darius,

Thank you for the files. Apologies for the delay, overall, the scaling of the BVH avatar looks incorrect, very long legs and very short torso…is this the true anthropometry of the subject?

For trials 1 and 2 you need to adjust the initial mannequin posture to better fit the initial position the avatar is in within the BVH file.

So within the TrialSpecificData.any files change KneeFlexion = 90 (both left and right) and then also change ElbowFlexion = 20 (both left and right). When I did this the model ran all the way through for me.

Trial 3 ran for me, what was the problem with this file for you?

For Trials 4-6, Something similar has been happening to some other users and we are currently trying to fix this. Here is a little bit more information about it:

Best Regards,
Christine

Hi Christine,

Thank-you for your help. I will try these adjustments. This is the correct anthropometric data as specified within xsens however i will adjust these to standard anthropometrics in future to ensure no issues if that is the current major problem.

Kind Regards,
Darius

Hi Darius,

I wanted to check back in to see if you got the models running on your end?

Best Regards,
Christine

Hi Christine,

i have got some of the files sent through working, however it seems every time i add a new file, some form of error will come. Making it hard to streamline the processing.
Attached is another file, this one cannot complete the BVH pre-process, do you know how to fix this?

Also, what is the best method to solving these errors?

Thanks,
Dariusbvh.zip (141.2 KB)

Hey Darius,

I think the BVH bug fixes discussed in this post will help solve most of your problems.

and more specifically here is a link to update your old models:

give it a try and let us know how it goes :slight_smile:

Best Regards,
Christine

Hey Christine,

Great! Ill keep you in the loop if there’s any issues.

Thanks for your help,
Darius

Hi Christine,

All files are now working which is great!

I am now wanting to plot graphs outside of anybody in excel, is this possible?
The export “model report” option does seem to be generating any files?

Primarily i would want to generate an excel sheet of all joint angles and additionally inverse dynamics sheet to plot individual and combine muscles of interest.

Thanks,
Darius

Hi Darius,

This is possible, please see the following Wiki entry for information.

Instead of copying and pasting a bunch of times you can also write some script to output all the joint angles and additional data you’d like:

And finally here is some information on how to process the .txt or .h5 data files using Python:

https://anybody-research-group.github.io/anypytools-docs/Tutorial/03_Working_with_output_from_Anybody.html

I hope this helps.

Best Regards,
Christine