getGlobalPosition problem

Hi’ i’m trying to track an object with a camera.
I’m having problems because when i track the 3dvector returned by getGlobalPosition() the vector does not correspond to the real object location.
How is it possible? To debug i draw a line from the origin to the object global position and the line doesn’t reach the object it has a sort pf offset.
How can i have the world coordinate of a ofNode?

Tx.
Gabriele