‘Upgrade’ director Leigh Whannell explains the importance of practical effects

In horror aficionado Leigh Whannell’s hyperviolent sci-fi thriller “Upgrade,” a paralyzed man, Grey Trace (Logan Marshall-Green), is given a new lease on life thanks to a brain implant called STEM (voiced by Simon Maiden). The tech not only allows Grey to walk again but also — in a few of the most visually inventive fight scenes you’ll see this year — pull off some “Matrix”-style ass-kicking to his own continued shock.

“I actually wrote down in the script, ‘Grey watches himself do these things with astonishment,’” Whannell told amNewYork with a laugh. “It’s one thing to write that sentence, it’s another for an actor to bring that sentence to life.”

We spoke with the writer/director about Marshall-Green’s impressively robotic performance, practical effects, and the not-so-distant future.

I was fascinated by how much Logan’s face managed to be so divorced from what STEM made his character do.

Logan threw himself into it. He worked really hard with a movement coordinator — who had worked with dance companies in Melbourne and Cirque du Soleil — to get that fluid grace that a dancer has. At the same time, he was working with stunt coordinators to learn the fight scenes. And he was also working in a wheelchair. So, he really did a lot of the grunt work to pull that off.

There’s so many great, gory practical effects in this movie. Was that important to you?

It meant a lot to me. I love practical effects for many reasons, one of which is pure nostalgia. I grew up in the VHS era. My top 10 of all time includes those sci-fi ’80s movies, from “The Thing” to “The Fly.” There was something beautiful and tactile about them. The things they were showing on screen, you knew they were actually there in the frame. Practical effects tend to get seen through this lens of kitsch, like, “Oh, they were OK for their time.”

I still to haven’t seen more impressive than “The Thing.”

“The Thing” is flawless. There’s nothing creaky or flawed about that movie. It’s funny because “Jurassic Park” is held up as being this groundbreaking CGI film, which it is. But if you watch it now, the stuff in it that I like the best is the practical stuff. That T-Rex attack is beautifully practical and it’s my favorite stuff in the movie, and the reason is, I can tell it’s real. CG should be used as a paint brush to augment what you already shot, not the only paint you use.

What were you looking for in casting the voice of STEM?

I didn’t want something that was too HAL from “2001: A Space Odyssey.” I wanted something that was like a pleasant, Siri-esque voice that became more and more passive-aggressive as the film went on. My car navigation says things like, “You missed the turn.” The voice hasn’t changed at all but we read passive-aggression into it. We think the thing is snapping at us. I find that fascinating, that human beings can take the same voice and color in through the emotions of what they think they’re hearing.

What’s your mindset when designing a future that’s only a few years away?

I didn’t want the “Blade Runner,” the “Akira” route. Flying cars, zeppelins in the sky with hologram advertisements. The hologram advertisements have really had their moment in the sun. I wanted this to be barely touching the future.

I remember this video game a few years ago called “Heavy Rain.” You were in the game, in the story, and all of a sudden in the detective station, you’re using holograms. I realized in that moment, pretty late into the gameplay, that we’re in the future. I love that approach. You could say that game was an influence on the film. It’s kind of like, what if you took “Se7en” and just bumped it a couple years into the future?