Finding angles from an IMU (Quaternions to Eulers)

1. How do you convert quaternion to Euler angles?
2. Why is quaternion over Euler?

How do you convert quaternion to Euler angles?

eul = quat2eul( quat ) converts a quaternion rotation, quat , to the corresponding Euler angles, eul . The default order for Euler angle rotations is "ZYX" . eul = quat2eul( quat , sequence ) converts a quaternion into Euler angles. The Euler angles are specified in the axis rotation sequence, sequence .

Why is quaternion over Euler?

Quaternion has the advantage that it gives better interpolation between keyframes for arbitrary rotations, compared to euler or axis-angle , this is often used for character animation and why its default for armatures. It also avoids the gimbal lock problem.