So… just a little about 3D. There are different types of ‘filtering systems’ that allow us to see movies in 3D. Before we talk about those, look at this picture of a line of bowling pins.
You can see from the drawing that the left eye sees the row of pins from one angle, while the right sees it from a slightly different angle. We need this ‘shift’ in order for the pins to appear in three dimensions. You can also see this by holding up one hand and blocking each eye (one at a time) and noticing the ‘shift’ of your upheld hand.
To make a 3D movie, you need to have a left-eye version and a right-eye version that can run at the same time. You also need a filtering system that blocks one of each movie versions for one of each eye. Here’s an over-simplified diagram explaining how 3D polarized filters work (these are the most common types of glasses given out in commercial theatres).
How to ‘free view’ 3D without glasses:
You can practice ‘free viewing’ (crossing your eyes until the two images overlap) with this still photo of Domo! (The overlapped image in the middle should appear 3D!)
And then there’s THIS!
And just for funsies… Wigglegrams!