How do Imax achieve the 3D effect?

Answer 1

I think that they use two cameras seperated by the space of our eyes (approx 2"). When the movie is playing, there are actually two movies playing at the same time. Both are exactly the same just slightly seperated from one another. The glasses allow each eye to view only one of these projections therefore, each eye is seeing somehing slightly different and the brain reconstructs this to be in 3D.