Mmh.. If you don't want it to move and rotate, try to link it to the camera. Otherwise if you just want it to face the camera try to use the lookAt expression:
Return type: Array .
Argument type: fromPoint and atPoint are Arrays .
The argument fromPoint is the location in world space of the layer you want to orient. The argumentatPoint is the point in world space you want to point the layer at. The return value can be used as an expression for the Orientation property, making the z-axis of the layer point at atPoint. This method is especially useful for cameras and lights. If you use this expression on a camera, turn off auto-orientation. For example, this expression on the Orientation property of a spot light makes the light point at the anchor point of layer number 1 in the same composition: lookAt(position, thisComp.layer(1).position)
The problem with your workflow is that the Element layer is 2d and the camera move is virtual. Without seeing the modified properties of your layers (press the U key twice) it's hard to know exactly how you have your project set up.
The problem you face is that you must create a 3D layer that always faces the camera, which is the easy part with the Auto Orient to Camera feature in the transform menu, and use that layer for the obscuration layer. The complicated part of that problem is keeping the 3D obscuration layer precisely lined up with the champagne glass as the camera moves. The most obvious solution is to render just the Element 3D layer with an alpha channel and then use that as a track matte for a solid layer that you make 3D. The anchor point needs to be precisely at the center of the glass and the layer must be oriented to always face the camera. If there is movement in the Element 3D shot other than a perfectly centered orbit around the glass then there will be some tracking or other fiddling with anchor points to deal with.
Without seeing exactly how you have your comp set up and complete workflow details it's really hard to give you much more than that.
How did you end up solving this issue? Please let us know.
I didn't solve it. I had to mask every frame in order to achieve the desired result.
I wonder if maybe you did not describe your issue as well as you could have. I say this because I would imagine
that you wanted all of the visible layers to be moving with the camera. It would probably look quite unnatural if they weren't.
Anyway, see if this helps