I have a simple animation where a cloth is pinned, and then have a wind start blowing and the “flag” is waving. Then I unpin the flag and it blows away. I have set the camera a restraint to track the “flag” (plane), and if I move the plane myself in 3D view with the manipulators (x,y,z), the camera tracks it OK. But it I run the animation, the camera doesn’t track the plane as it blows away. Even if I bake the animation, it doesn’t work. Is it possible to do what I want, so that the camera will track the plane (“flag”) as it is blown away by the wind?
not really, see the track constraint is targeted to the objects origin point, which while the cloth is blowing around, the origin point remains in the original position. so, you need to bypass the origin point of the flag some how…
fortunately, this is easily done 
add an empty to your scene, and then shift select your flag, so bothe the empty and the flag are selected with the flag as the active object. go into edit mode and select a vertex in the center(ish) of the flag and press ctrl P to create a vertex parent to the empty.
in object mode again, add the track to constraint and target the empty, now when the flag flies off; the empty, being a child of the vertex of the flag, will follow along and the camera will track the empty as the empties origin point is being the thing that is actually parented to the flag 
hurrah!
1 Like
Thank you! It works fine. I had tried parenting an empty, but not to just a single vertex. Now it is exactly what I wanted.