OpenSense Calibration file

[Giacomo Di Raimondo]

Hello to the OpenSim forum and community.
I started to use the OpenSense tool and the kinematic results compared with the stardard pipeline of OpenSim seem really promising.
I collected my dataset with Xsens sensors, and I have all of them .mvnx format. Xsens company provides a tool fro load and read that format file in Matlab, so I can get the orientation directly from there, jumping step one and two of your OpenSense guide. Then, I converted the files from .mat in .sto format (getting the orientation.sto).
Therefore, in step three - Calibration - I used that orientation.sto and the relative scaled model to get the model calibrated.
My problem is that sometimes the rotation matrix(-pi/2, 0, 0) does not work. So I have to use a different rotation (e.g. -pi/2, pi +- n, 0).
The question is if it is possible that the .xmnv format give to you a different orientation than the one get from step one and step two?
Because sometimes is very difficult to understand which is the correct rotation matrix.

To sum up:
Is it possible to use .xmvn orientation instead of Xsens text format like in your example?

Is this an Xsens problem or OpenSense one?

Thanks