Though there’s evidence that the audience’s appetite for 3D films could be diminishing, some companies are taking entertainment one-step further: the fourth dimension. A 4D film is simple. It’s a 3D movie with physical effects in the theater for that extra dimension. A good example is Muppet Vision 3D at Disney-MGM Studios in Florida where you watch a 3D movie, but things brush up against your legs. Internationally, a South Korean company called CJ 4D Plex is currently converting regular theaters to 4D and, reportedly, will test the technology in Los Angeles later this summer. After the jump, check out photos from a 4D Plex theater, read more about it and find out how Samsung might have finally perfected Smell-O-Vision.