Does anybody have an example use cases of quaternion function in BB3? I cant able to find in any of game templates. Entity rotationQuat( quaternion ) Entity setRotationQuat() http://download.buildbox.com/buildb....html#buildbox-entity-rotationquat-quaternion

You don't need to use those. They're most likely used to ensure there is no gimbal lock on rotations. You can just use the normal rotation function and that probably translates to quaternions for you behind the scenes so you don't have to worry about rotation issues. Also since rotation functions use Euler angles, these angles only go up to 360 degrees, so if you have a rotation that goes beyond that 360 number you can run into issues during gameplay. That is what quaternions also solve since they're not dependent on fixed numbers. So a calculation is done to translate those Euler angles into quaternions and then back again, ensuring you get the desired results.