transformere_web.jpgNEW YORK—Transformers has shaped what the summer movie is: its quick-cutting bombast, its visual-effects flourish, its capacity for mass destruction.

This summer, Transformers: Age of Extinction’(June 27), the fourth film in the franchise, comes with a revamped cast led by Mark Wahlberg. Michael Bay, who also produces Teenage Mutant Ninja Turtles (Aug. 8) later in the season, is well acquainted with the scale of the modern blockbuster.

“I’ve been doing these movies a long time,” said the 49-year-old Bay in a recent break from the editing suite. “When all is said and done maybe 3,500 people will have worked on this movie. It’s one day at a time. You can’t panic. My pep talk to everyone is: This is when the pro (expletive) starts and separates the men from the boys.”

Age of Extinction subs out the sometimes combative Shia LaBeouf with an older, more established action star in Wahlberg. It’s planned as the first of a redesigned Transformers trilogy.

Bay and Wahlberg first connected on last year’s comic crime caper Pain & Gain, a relatively low-budget project for Bay and one of his most critically acclaimed films.

Wahlberg has already vowed that Age of Extinction will be the biggest movie of the year. While optimistic, it’s not out of the question. The last Transformers film, 2011’s Dark of the Moon, made more than $1.1 billion worldwide.

“It feels fresher with the cast,” says Bay. “It’s like when you get the new ‘Batman’ franchises, things get dressed up in a different way. I think the franchise still has a lot more to offer.”

Age of Extinction is a co-production with two Chinese film companies. A month of shooting took place there, and several Chinese actors were cast through a televised reality show talent search.

Such is the global natural of the big-budget summer movie, a sprawling operation that takes a unique acuity to assemble.

`”I don’t write notes,” says Bay. “I put the movie in my head.”