Production designer Guy Hendrix Dyas was atop a snow-covered Fortress Mountain in Alberta, Canada, shooting the final scenes for “Inception” in late November 2009, when he got the call on his cell phone: Steven Spielberg wanted to talk to him as soon as he got back to Los Angeles. Two weeks later, he was sitting in the director’s office at DreamWorks discussing a bigscreen adaptation of Daniel W. Wilson’s sci-fi novel “Robopocalypse.”

“The book was still kind of being written,” recalls Dyas, who had previously worked with Spielberg on 2008’s “Indiana Jones and the Kingdom of the Crystal Skull.” “And it was very unclear as to whether Steven was going to be directing this or producing it. [But] he had a twinkle in his eye and a very clear vision of what he wanted to do with the material.”

Production designers are almost always the first to come on board a film after the director is hired, but the period of time they’re given to prep prior to principal photography varies wildly from project to project.

On Quentin Tarantino’s “Inglorious Basterds,” production designer David Wasco had a mere 10 weeks.

“It was a panic,” says Wasco, who works with his wife, set decorator Sandy Reynolds-Wasco. “But I was able to get location resources from both ‘Valkyrie’ and ‘The Reader,’ ” the former of which was set in WWII like “Basterds.” “And Roman Polanski was starting ‘The Ghost Writer’ at Babelsberg Studios in Germany at that same time, but he lost his funding and it freed up all these stages there, and I was able to get the best art department for support.”

Dyas got an exceptionally early start on “Robopocalypse,” even by big-budget tentpole standards. He hired his first three art department workers in late January 2010, and 1½ years later he’s still “on the cusp of (full-blown) pre-production,” working with a team of a dozen art directors, artists and model makers, while Spielberg prepares to shoot the historical drama “Lincoln” starring Daniel Day-Lewis in the fall.

Spielberg has committed to directing “Robopocalypse” next year for a 2013 release. In the meantime, he and Dyas stay in constant communication on the phone, with the occasional face-to-face meeting to review artwork and models.

The process “gives the director an opportunity to focus on how he wants to approach the film,” Dyas says. “Whether it’s going to be a live-action or (animated), what countries we’re going to shoot in, whether it’s going to be stages or locations — these are all questions that can really be answered in a director or producer’s mind once they start seeing things on paper.”

These days, a film’s look isn’t necessarily the first thing a production designer grapples with.

“It may be the third or fourth thing,” says production designer Jess Gonchor, coming behind such considerations as tax incentives, available quality crew, weather and other financial and logistical factors. “We didn’t know where were we were going to shoot ‘True Grit’ until we were just about out of time. Basically, I was roaming the countryside for a couple of months before we figured it out,” choosing Texas and New Mexico, the latter of which boasts a 25% tax rebate.

The director’s involvement in the process varies.

“A Wes Anderson would be concerned with the color of an eraser that’s in someone’s pocket,” says Wasco, who worked with the helmer on three films, including 2001’s “The Royal Tenenbaums.” “Michael Mann, the same thing. And they would be right about that.” Whereas Oren Moverman, director of the upcoming “Rampart,” “knew that the big picture would come out good with us putting our stamp on it.”

On the HBO series “Game of Thrones,” production designer Gemma Jackson worked with five directors over the course of the 10-episode season. When Tim Van Patten came on board to helm episodes 1 and 2, Jackson had largely worked out with the look with writer-producers David Benioff and D.B. Weiss.

“We just fine-tuned the worlds and the details” for both esthetics and economics, says Van Patten. For instance, on locations in Malta and Belfast, Ireland, “we tried to avoid building in warehouses and soundstages and instead used practical locations, then (augmented them) using visual effects,” he says.

On “Cowboys & Aliens,” production designer Scott Chambliss was joined by visual effects supervisor Roger Guyett about two months into his eight of prep. The two worked together to create the proper venue for the climactic alien encounter so it was not a jarring transition from the Western environment, helping solve a third-act problem that had been vexing the filmmakers.

“I always feel that production designers are visual storytellers,” Chambliss says. “We’re there to do the visual version of what the writers have done with words and what the directors are going to do with the actors. We just have different tools with which to tell the story.”