Exporting IMU Data from C3D files.

[Marie Schmidt]

I have a similar problem by running c3dExport.m but the error occures by calling on osimC3D in line 65 ''No method 'read' with matching signature found for class 'org.opensim.modeling.C3DFileAdapter'.''

osimC3D.m is not on your Matlab system path-- you will need to add it.

osimC3D is in my Matlab path

-Matlab2019b
-WIN 10
-IMU Data by Xsense

Has anyone an idea how to deal with this?

Cheers

[jimmy d]

Do you have OpenSim 4.0, downloaded from the here? Have you setup OpenSim to work with Matlab and tested that it works?

Also, the C3DFileAdapter only supports marker and forceplate data which is described in the documentation. Is your C3D data from an Xsens system?

[Marie Schmidt]

Thanks, for your quick replay.

OpenSim 4.0 is installed and is also setup with matlab. I captured the IMU Data with Xsense (MVN Studio 4.4) and exportet them to c3d.

My overall goal is to simulate based on the captured data a model in OpenSim and calculate some muscle parameters as fiber length.

Cheers

[jimmy d]

The C3DAdapter in OpenSim probably won't be able to read the IMU data from the C3D since it can only access Markers and Forceplate data. Can you output the Xsens data as text (.txt) files? We are working on supporting the tracking of IMU orientations, and have been using Xsens data for testing/development, but the interface is to txt files exported from Xsens.

[Marie Schmidt]

I can not directly export .txt fiels. However I can convert them. But they have a different format than the example fiels (MT_012005D6_009-001_00B421E6.TXT).

[jimmy d]

I started a new topic for your issue because it wasn't related to the original thread.

You should check the MVN documentation and reach out to Xsens user support. Xsens can output the raw IMU data in txt file format and that is what the OpenSim IMU data converters. Otherwise, you will have to write your own converter that transforms Quaternions in txt file to Quaternion Storage files (OpenSim format).