Calculate the rotation angle

[MysteryNull]

Thank you for your work! I tried the code and just want to know how to calculate the rotation angle from the rotation matrix of the ellipsoid obtained from the program？

[aleksandrbazhin]

I guess you can use eigen vectors (evecs) which are returned from ellipsoid_fit() and calculate their angles. As they are orthogonal, you can take any vector you like and calculate the rotation angle from X axis to it.

[MysteryNull]

How to caculate the angles with one eigen vector, thank you.

[aleksandrbazhin]

Sorry, I was wrong - you can not calculate Euler angles to a single vector, the roll angle is undetermined then. I didn't use any of the stuff for a long time. In general Euler angles are more tricky then they seem, but there's nothing too difficult. I suggest you do your own research.