Above is a still from the final comp ( pic A ) . I did the matte painting in Photoshop with a picture given by the client . I provided layers ( see bottom , pic E ) and a mask of all the windows to render a reflection pass . CG artist managed the camera projection that allowed for recreating a subtle camera movement as well as inserting that strange CG octopus passing over the buildings ( see thumbnails of the final shot , pics B , C , D ) .