The arguments I am using are: -s "10%" -a 25 -o 20 -m backdrop -u 50 -p 10 -l 15
but for some reason the resulting image comes out looking like this, with no 3d perspective at the spine: http://prntscr.com/emw1wu
not too sure what I could be doing wrong, any assistance would be greatly appreciated, let me know if there is any other info I can provide to help clarify the issue or aide to a solution.

Using IM version 7.0.5-3, using both 3DCover and 3DRotate scripts