Quote - You're very welcome :)

On a side note try importing a human head, once with normals flipped and once without. Then rotate the scene slightly. You'll be surprised at what you see.

hi sir, not sure if i got your point. but i imported a flipped human head( hollow ) , turned it to 180 deg with respect to y axis untill 'he' facing backward, so i rotated the camera slightly, surprisingly the head rotated along with the camera as well LOL... Reminds me of an optical illusion i've watched online few months ago!