camera attach to an actor

Hi,
I have a camera attached to my vehicle by
car_sn->attachObject(mCamera);
this have a minus, the camera is rigidly attached to it.
Do you have a better idea for camera attachment to the actor so the camera would not to be moving vertically as the vehicle?

Just get the vector coordinate of the car, change "Y" to what you want it to be, then apply it to your camera.