Robert Rodriguez has been a fixture in the Austin film scene for decade, known for stretching a dollar until it screams for mercy. His 1992 debut, “El Mariachi,” which famously shot for about $7,000 (plus $200,000 of post-production), locked him into the Cheap Film Hall of Fame and became a key flick in the early 1990s American independent cinema revolution.

Since then, Rodriguez has made action pictures (the so-called "Mexico trilogy" of "El Mariachi," "Desperado" and "Once Upon a Time in Mexico"); psychedelic family films (hello, original “Spy Kids”); horror films with good-looking, Irish-American guys named Clooney before they became good actors (“From Dusk Til Dawn”); grindhouse flicks (that'd be “Grindhouse”); and extremely faithful comic book adaptations (“Sin City”). He also launched a TV network, “El Rey,” from his Austin-based Troublemaker Studios and generally stayed master of his domain.

But Rodriguez has never worked with an enormous, blockbuster budget until now.

“Alita: Battle Angel” — directed by Rodriguez, produced by "Avatar" filmmaker James Cameron (for whom the film was a pet project) and filmed in Austin — clocks in with a budget estimated at $150-200 million. It was a massive undertaking, using motion capture technology to create the main character from actress Rosa Salazar's real-life performance. But the scope was perhaps not as alien to the director as it might first seem.

We sat down with Rodriguez to talk all things "Alita." This interview has been edited and condensed for clarity.

Austin360: When did you first hear of this project?

Robert Rodriguez: Well, I heard about the project in early 2000. I saw a story online that said "Battle Angel" was (James Cameron's) next picture. I said, "OK, I could see why he would like to do that: sci-fi, cyborgs, strong female character."

Then 15 years went by. I went to visit him about four years ago, just social lunch, you know, just to catch up. He was showing me all the artwork he was gonna be doing in the next several "Avatars" — mind-blowing stuff. You know that's gonna take a while.

So I was like, "Well, when are you ever gonna do Battle Angel?"

"I probably won't have a chance to make it," he says.

Then a little later, I am almost in my car, he says, "Do you have 15 minutes?"

Did Cameron show you what he had planned for "Alita"?

Yeah, he'd written a 186-page script, about a three-hour script, and made an eight-minute art reel with narration and everything. And that's when I first saw Alita with the manga eyes and the porcelain arms with engraving on them. Just stunning. He was going to direct that in 2005 before "Avatar," before they had the right technology. (The Na'vi characters in "Avatar") were aliens, so you kind of get away with it not being completely real, but you couldn't fudge a human character.

I checked out the script, and he had crafted this more cinematic story than the manga presented. So I wrote him back and I said, "The script is awesome. It's all there. It's just too long. I would just cut it down, but I love the father-daughter relationship. I love the relationship with the boy. I related to (Alita). If I can relate to a 13-year-old girl, then that means that's a universal story." I wrote in the email, "How many heads to I have to collect to work on this thing?"

A couple of hours later, he wrote back, "You've collected enough heads, call me tomorrow." I was like, "Oh, yeah!”

Did you start working on the script?

Yeah, I didn’t even know if I could cut five pages out of this thing, but I'm gonna try and just edit it down. (Cameron) writes so clearly, like a writer-director, not just like a writer. You can see every shot in every scene. I left all the heart and all the characters and all the story, cut some of the spectacle and combined some characters.

And he loved it. He said, "I managed to get from beginning to the end without you cutting any of my favorite scenes. I don't know how you cut 60 pages out of this thing."

I said, "I just took out the stuff I knew you probably wouldn't find important." And so he said, "OK, so that shows that you're the guy to direct it."

So he gave it to me. That was the end of 2015.

What was your relationship with Cameron like, with you as director and him as producer, on a project he had wanted to do for such a long time?

We almost did something together (before "Alita"), where I was the director and he was the producer, but I went and did "Sin City" instead. I knew we got along because we both came from the same background. One time he came to my house and he said, "I hear you have (digital film editing equipment) Avid in your living room." It was unheard of. Nobody was doing that — director cutting his own movie. I was cutting "Desperado," "Dusk Till Dawn" and "Four Rooms," all at the same time, myself. And he said, "I'm doing that! I hate working with editors. I'm gonna tear down a wall in my house. I'm gonna put in an Avid. I'm gonna cut my next movie." And he did.

As for "Alita," he said something in the press like, "We're gonna be like making a go-kart together." And it really is like that. He's like the cool older brother who, if you don't know how something works, he says, "Come here, kid, I'll show you."

When we were about to start, he said to me, "You know, there's nothing new you haven't done on this movie except for performance capture, but I'll show you that in a week."

He's a great mentor. He said "Make it your movie," but I wanted to make a James Cameron movie.

How does you making a James Cameron movie work?

He told me he believes science fiction and fantasy have to be completely believable, or you don't buy the fantasy. So I had to throw out everything I normally do. No green screen. Build real sets, real locations, real actors around Alita. So, I just changed my methods to do it in that style. I really wanted to see how he does it. You know, there's gotta be systems and processes that he uses. It really was a look behind the curtain, but now that I've done the whole process with him, it's like, I hate to tell you, there's really no processes or anything. He's just a frigging genius.

Yeah, it’s tough when that happens.

He can see things others can't. It's humbling, but it's super inspiring to just even know somebody like that. They are very rare breeds, and if you can hang with them and impress them at all enough so they can bring you into their inner world and tell you about what they're up to, it's the greatest gift in the world.

You are also someone who has stayed mostly away from studios, period. And studios usually have the big bucks.

I stayed away from studio movies in general before, because I had so much freedom in my lower-budget stuff. If I did a studio movie, it would be theirs. They would say, "This is our franchise, would you like to direct it?" They're gonna tell you who to cast, how to end it, all that, because they want their money back. Totally understandable. It's a lot of money.

But "Alita" was like, "Oh, I'm not making a movie for a studio. I'm making a movie with my buddy Jim."

This is like making a big independent film. We just gotta please ourselves, and so it was really the best of all worlds. We had the budget to do anything we wanted, and no one could tell us not to. It's like making the movie with your own personal Terminator next to you. I mean, you're totally protected.

Do you feel different as a director after directing something this big?

People say, "Well, you made such low-budget, do-it-yourself movies, and now you're doing this big movie." Well, that's Jim. He came from the Roger Corman school. It's just he drifted off so fast you forget he started that way. He can still do every job. He's still like that.

I used to wonder if he would dabble in low-budget (films) again. But he won’t, and I know he won’t, because a movie like "Alita" or "Avatar" puts the filmmaker, for the first time, in the seat of the audience again. You are shooting blind in a lot of ways. You don't know what a shot will look like. Shots come in (with the effects completed), and you're stunned like an audience member. I didn't really see it and feel it until just a few weeks ago when I finally saw ("Alita") all put together. Some of the shots, I'm like, "When did we shoot that?"

Austin-filmed "Alita: Battle Angel" opens this week in theaters. Find Joe Gross' review, as well as a brief history of the character's journey to the big screen, at austin360.com.