The idea behind the making of 3D (three-dimensional) movies started with concept of stereoscopy.
This device looked like a binocular but with slides put in which were viewed for 3D image.
The slides have two different pictures which are combined for making one picture, but both the pictures are actually same scenes.
The same idea of stereoscopy was used in the making of 3D movies.
3D movies are shot using the real actors by using a 3D camera that has two different angles fitted in it.
Thanks to the digital technology as special effects can be added easily while maintaining its realistic integrity.
Animated 3D movies are created the same way and digital technology makes movements clear and precise when viewed using 3D glasses.
You need to view these movies using special 3D glasses as if you do not put them on you will see that edges of every person or object appear blurred.
Therefore, 3D movies appear to be more realistic and lively.
For instance, when you are seeing a 3D movie, baseball coming towards camera in 3D movie will almost hit viewer's faces causing jolting reaction.
Therefore, to complete equation of 3D movies 3D glasses are essential.
These glasses once were made from paper with red film on upper side and blue film on lower side, now most of them look such as giant sunglasses having grey lenses.
They are polarized and are designed for displaying one picture to one of your eyes and other picture to other eye which results in a stereoscopic image that creates illusion.
This illusion creates effect, because of which the objects seem to come closer enough such that audience feel as if they can touch it.
You will find these glasses easily on the internet as many websites sell variety of 3D glasses.
They are a indispensable device while watching 3D movies.