Re: I would like to know how 3-Dimensional movies are made.

In a nutshell, it's both.

Humans see the world in 3D. Since your eyes are a few inches apart, they see slightly different versions of the world. To illustrate this, hold one finger up, close to your nose, and look at it with just one eye open. Switch eyes. The finger looks like it is jumping back and forth.

Your brain combines the images seen from your eyes and uses the differences to determine how far away something is. The closer something is, the more of a difference there is in the images your eyes see.

3D pictures (and movies) play a trick on your brain by showing two different pictures to your eyes. Your eyes see two pictures that are nearly the same, but some things are slightly shifted in one picture, causing them to "jump out" of the scene.

The most common method for showing different pictures to your eyes is to use different colors. Pictures made using this technique are called anaglyphs. One of the images is drawn in red, and the other is drawn in cyan (a blue/green color). These images are combined into one picture. To view the picture, you wear glasses with colored lenses. Each lens filters out one color, allowing you to see the image that was drawn with the other color. Your eyes see two different images, your brain does its customary correction for the differences in the images, and the picture (or movie) appears in 3D.

You can read about other methods for showing different pictures to the eyes here.