In an interview with Vanity Fair, James Cameron had this to say about Piranha 3D:
I tend almost never to throw other films under the bus, but that is exactly an example of what we should not be doing in 3-D. Because it just cheapens the medium and reminds you of the bad 3-D horror films from the 70s and 80s, like Friday the 13th 3-D. When movies got to the bottom of the barrel of their creativity and at the last gasp of their financial lifespan, they did a 3-D version to get the last few drops of blood out of the turnip. And that’s not what’s happening now with 3-D. It is a renaissance—right now the biggest and the best films are being made in 3-D. Martin Scorsese is making a film in 3-D. Disney’s biggest film of the year—Tron: Legacy—is coming out in 3-D. So it’s a whole new ballgame.