~ Six degrees of freedom (6DOF) refers to motion in three dimensional space
~ i.e. to the ability to move forward/backward (x-axis), up/down(z-axis), left/right(y-axis)
~ and combined with rotation about three perpendicular axes:
~ >Yaw (z)
~ >Pitch (y)
~ >Roll (x)

Because the movement along each of the three axes (x,yz) is independent of each other, and
independent of the rotation (yaw,pitch,roll) about any of these axes, the motion has six degrees of freedom.

>Helicopter has 6DOF.

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