Hi:) I have small probelm.
I would like to export rotation data to xml file. The main problem is that I want to import that data in 3ds Max. In 3ds Max rotation is rotation_quaternion not rotation_euler. I thought that it is not problem because blender has got rotation_quaternion. I do not know why but if I am changing rotation of object[0].rotation_euler

is changing and object[0].rotation_quaternion

is still the same(

Quaternion((1.0, 0.0, 0.0, 0.0))

I would say that it is not normal,isn’t it?

Try a bpy.context.scene.update() call after you change your Euler to have Blender update the quaternion data.

I didn’t changed[1].rotation_mode = 'QUATERNION'