Hi, I have had a similar problem as you where having but in my case a barrel was cutting down in size when moving the camera left or right. I opened a .3ds file in photoshop and then saved as a psd to get my 3d object into AE. When I finally realised the imported image size was different than my composition size in After Effects, I altered them to match and hey presto, that did it, … well, I am doing it again properly now.