Robert Rodriguez is a ground-breaking movie director whose first film, “El Mariachi,” was made on a micro budget of $7000 (with another $220,000 after it was purchased for release).  He is known for striking visuals and ultra-violence in movies like Once Upon a Time in Mexico and “From Dusk til Dawn” and for wildly imaginative family movies like Shorts and the Spy Kids series.  Rodriguez continues to operate outside of the film-making establishment.  He has established his own film-making set-up in his home town of Austin, Texas, and works with his family, writing, editing, shooting, and directing himself, with his ex-wife, Elizabeth Avellan, and his sister as his producers, and his cousin Danny Trejo appearing in many of his movies, including this one as “Uncle Machete.”

I spoke to him about the fourth in the “Spy Kids” series, this one in “4D.”

What does 4D mean?

It’s been a very scrappily innovative series since the beginning.  In “Spy Kids 2” we started shooting digital.  And with the digital camera, I thought, “Hey, I think I could bring 3D back.”  It hadn’t been tried in 20 years.  I tried it with “Spy Kids 3” and that became the biggest “Spy Kids” of all, and Jeffrey Katzenberg took note of that and said, “We’re really going to bring 3D back.”  In keeping with the series, with everyone being 3D, we really had to go to 4D.  I remembered a film with “Odorama” called “Polyester.”  That wasn’t a family film, but I said, “That would be a terrific gimmick in a family movie and I’m sure the technology has gotten a lot better.”  It has — everything doesn’t smell like batteries.

How do you keep the smells from colliding with each other?

They don’t do that any more.  It used to be that all the smells had a real chemical base to them and they all started smelling the same after about the third or fourth one. Once you got to the dirty socks, everything kind of smelled that way.  But now they call stay really distinct.  The technology has really gotten better, and I didn’t have to do anything but pick which flavors I wanted and they put them on the card for me.  And it’s free, just as with the 3D movie where we gave the glasses away for free as well.  It’s a level of interactivity that you just don’t get in a movie.  Kids are so into interactive things like video games for entertainment.  A movie can be very passive by comparison.  This brings back the active excitement of putting yourself one step closer to the actors and the characters on screen because you’re smelling exactly what they’re smelling at the same time.  In the tests we did, the kids felt it was really a home run as far as making them feel they were a part of the action.  That’s what you hope to do with another dimension, just make them feel closer to what is going on in the movie.

One of my favorite things about theThe Spy Kids Trilogy is the fantastic gadgets the kids get to use.  What’s your favorite gadget in this film?

There’s a dog they could never understand who watches over the kids in the house and he turns out to be a robot dog voiced by Ricky Gervais.  That’s probably my favorite.  He can do just about anything.  He’s like a multi-tool gadget knife and James Bond car all built into a dog.  And another of my favorite gadgets is the hammer hands that the boy puts on, like Hulk hands — they can smash through anything you touch.  I think my little boy would really love them.

I love the way the “Spy Kids” movies have a lot of action but very little violence.

There’s a very comic line to the action and a lot of it comes back on the kids themselves, so it really promotes adventure and not violence.  That’s what parents have always loved about the series.  I’m always very careful not to put anything over the kids heads in my family films.

Is there anything you wanted to include in this one that you didn’t get to do?

I wanted to do a James Bond-type song over the end credits with the dog’s head like Sheena Easton but we didn’t make it happen.  Maybe next time!

How do you cast a villain? What do you look for?

You want a surprising quality.  The villains in my movies are never really villains; they’re just misguided.  The children always teach the villain a lesson.  They don’t defeat him.  This movie’s villain is the Timekeeper, and he’s very much me.  I’m always worried about time there is.  Seeing my kids grow up so fast, I always want to freeze time.  So he is just a little eccentric and it turns out he has a tremendous amount of heart.  He’s a super-villain with family values.  You need someone who’s a real chameleon.  I knew Jeremy Piven could create three or four distinct characters and pull it all together.  He has a lot of heart as an actor.

The “Spy Kids” movies are always about the importance of family.  In the earlier movies, there was a typical nuclear family but in this one there’s an issue a lot of kids have to deal with — adapting to a blended family.

I got the idea from seeing Jessica Alba on the set of “Machete” with her baby, but dressed for filming.  I thought, “Wow, she kind of looks like a spy, and having to deal with this baby — wouldn’t that be cool as an element in the ‘Spy Kids’ movies.”  I said to her, “You should be the mother in the new ‘Spy Kids’ movie and have to take the baby on a spy mission.”  She said, “I’d probably have to be a step-mother because I am too young to be the mother of school-age kids.”  So I thought, “that’s even better.”  She’d be harboring this big secret and kids are really sensitive.  They know when someone is hiding something from them.  So they don’t really like her as a stepmom because they can tell she is not being honest.  Through this mission they find out what her secret is and everyone becomes closer because of it.  I thought that would add a really great wrinkle to the whole idea of what family means.

I also like the way the kids in your movies are real kids but also very brave and capable.

Kids crave things that empower them.  Seeing kids on screen flying around saving the world gets into their dreams and they identify with it and pay-act it out.  I saw it in my own two youngest, who weren’t born when the first ones came out.  I told them I made them but they did not really understand what that meant.  They just like them and pretend to be spies and to be strong.

And Machete is in this movie?

Danny Trejo’s code name in the original “Spy Kids” movie was Machete.  We were doing a nod to this idea for a movie that we never got off the ground.  We had been talking about doing a “Machete” movie since “Desperado.”  So we said, “We should make your character’s code name ‘Machete.'”  His name was really Isadore.  He’s not the same character as in the movie “Machete!”

That’s good to know, but I hope he doesn’t text.

No, he doesn’t text.  Some things are sacred!