A 3-D (three-dimensional) film or S3D (stereoscopic 3D) film is a motion picture that enhances the illusion of depth perception.
Derived from stereoscopic photography, a special motion picture camera system is used to record the images as seen from two perspectives (or computer-generated imagery generates the two perspectives), and special projection hardware and/or eyewear are used to provide the illusion of depth when viewing the film.
3-D films are not limited to feature film theatrical releases; television broadcasts and direct-to-video films have also incorporated similar methods, primarily for marketing purposes.
3-D films have existed in some form since the 1950s, but had been largely relegated to a niche in the motion picture industry because of the costly hardware and processes required to produce and display a 3-D film, and the lack of a standardized format for all segments of the entertainment business. Nonetheless, 3-D films were prominently featured in the 1950s in American cinema, and later experienced a worldwide resurgence in the 1980s and '90s driven by IMAX high-end theaters and Disney themed-venues. 3-D films became more and more successful throughout the 2000s, culminating in the unprecedented success of 3-D presentations of Avatar in December 2009 and January 2010.
reference ：http://en.wikipedia.org/wiki/3D_movie
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Now Time For Relax ！
Please enjoy the Short Video for the film Avatar :)
