Normalize the Velocity of an animated Bird

[Tridae]

I'm trying to normalize the velocity of an animated Bird. (not sure if normalize is the right word)

 

The bird was animated to flap and fly along a path in XSI then exported to alembic. 

I want to emit fluids off the bird using the wing flap velocity WITHOUT using the velocity of the bird body moving through space.

 

How would I go about getting rid of the forward velocity?

 

I tried using a centroid point to subtract from the bird velocity in a VOP with hopes that it would leave me with only the flapping velocity but no luck there. 

 

 

I've attached a file with an example setup. 

Any help would be appreciated, I think I'm missing something simple. 

normalize bird velocity_v01.hip

[JuriBryan]

lay down a transform node:
put $CEX $CEY $CEZ into pivot, copy that channel into transform and put a - in front each one.
now you bird will stay at the center points with out moving in space whiles rotational animations and geometry deformations stay the same.
calculate vel on that and copy the values to your animation.
done

[Tridae]

Thanx!

 

That did the trick. So simple too.