Bridgeofstraws wrote:
> Hello,
> 
> I have been working on a jet fighter model for over 6 months now and I have come
> to the point where it is worthy to be animated.  The only thing is, I have no
> idea where the rotation point of the plane should be.  Let me elaborate.  From
> my understanding, an airplane may rotate along the yaw axis (the rotation the
> rudder controls), the roll axis (which is controlled by the ailerons), and last
> the pitch axis (controlled by the elevators).  In most diagrams I've seen these
> three axis of rotation meet at a single point and this is the point I don't
> know how to find.  My only guess is that it would be the centroid.  Any help
> would be greatly appreciated.
> 
> Bridgeofstraws
> 

It should be the center of mass.  However, there's no obvious way to find the center
of mass unless you know the mass density of each element of the aircraft.

For each element of the aircraft, of center of mass position r_i, and unit mass m_i,
you can calculate the net center of mass r-com:

r-com = sum_i { r_i m_i } / sum_i { m_i }

where r-com and each r_i are spatial vectors with x, y, and z components.

Dan

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