We saw the poster and trailer for Spy Kids: All the Time in the World, which prominently advertize that the film is in 4D. You might have wondered what the fourth dimension promised by Robert Rodriguez would be, or you may have guessed that the movie was going all the way into the land of gimmick, rather than just messing around on the borders.

The fourth dimension is smell, which means that Robert Rodriguez is now in the rare company of filmmakers who have used processes like Smell-O-Vision, AromaRama, John Waters’ Odorama and the fragrance-enhancement used for some showings of Terrence Malick’s The New World. Yes, you read that last bit correctly.

USAToday has the director saying that he needed something new after Spy Kids 3D (which helped kick off the current wave of 3D films) and settled on using odors that are “tied to the plot.”

This system, Aromascope, uses a card similar to the scratch and sniff one John Waters had distributed with Polyester in the early ’80s. It has eight scents activated by merely wiping a finger across each one. From anyone else — or anyone doing it seriously, I suppose — the idea would be ridiculous. But for a kids movie that is the latest in a franchise that seems to be out of gas, why not?

But what’s that Terrence Malick bit about? Turns out that in 2006, a Japanese company tried to augment his film The New World with an AromaRama-like system, which piped odors into the theater at key points in the film. Seriously. Here’s the press release. Mentioned here, too.