Ok thank you alread
I found out that the shown rotation matrix is for fixed XYZ axes (not relative), I will update later which rotation matrix I'm now using.
I found out the correct 2nd angle by drawing:
rotations - GeoGebra
Now I will search for the way to find this angle.
I want to rotate an inclined plane to achieve a flat surface.
I think I can use the Euler angles to perform this operation.
Using following data:
and following rotation matrix
I think you can make the plane flat by following rotations:
1: rotation around x-axis by 45°
2: rotation around...