I see that you're using element. The layers are actually 2D they just act 3D and they are moving off the stage because they are not really on the stage it just looks like they are.
You'll ave to parent all of your 3D objects then move the group the the exact center of the composition.
Thanks for the reply.
Can you suggest another way of doing this?
I want a concert stage with these models and a 360 look around the stage?
You simply need to position them properly using the Element 3D group controls. Even multiple instances of the effect will align properly, since they use the same camera, you just need to put everything in the right place. As Rick suggested, it would be best to start by zeroing them out and then moving them based on a common origin/ reference point.