We see things in relief because of our bonocular vision. Because our eyes are set about 6.5 cm apart, each eyes sees object from a slightly different prospective. Therefore, to recreate the impression of relief, two different view must be taken and then superimposed by a system which sends each eye the corresponding image. The two images are recorded side by side on 35 mm. film. The projector is equipped with a special twin-prism lens which superimposes the images via two inverted polarizers.
T o preserve light polarization, the projection screen is metallic.
The glasses through which the viewers sees the 3-Dimension image are also polarized.