Two cameras shoot the same image from opposite directions. When the images are pieced together, it creates a three-dimensional effect for the viewer.
Original 3D movies contain images in red and blue, requiring audiences to wear glasses with red and blue filters.
Today's 3D films require theaters to use two projectors, one showing images for the left eye and one for the right. Each projector contains a filter that regulates waves of light.
Audiences wear glasses that allow the left eye to only see light from the left projector and the right eye from the right projector. (The glasses are given to viewers at the theaters and then returned.)
