If “Cloud Atlas” was an acting dream — the chance to play six roles in one movie! — it was a casting challenge of epic proportions for Lora Kennedy.

Warner Bros.’ exec VP of talent used a grid to keep each potential actor’s various roles straight during the casting process. The goal, she says, was to find a thesp who could plausibly evolve into the various characters he or she embodied over the course of the time-traveling movie directed by Andy and Lana Wachowski and Tom Tyker.

Tom Hanks got the interconnected roles of an opportunistic seafaring doctor in 1849, a nerdy nuclear plant employee, brutish Scottish author and goatherd in the future, among other characters. And Halle Berry embodied a native woman, a crusading 1970s journalist and a male doctor in futuristic 2144 Neo Seoul, plus a Caucasian beauty and an emissary from a advanced human community.

The production has drawn some heat for casting Jim Sturgess as an Asian, but Kennedy points out that is just one of shape-shifting roles in the movie. Korean actress Doona Bae, for example, plays a Mexican woman and an abolitionist in San Francisco circa 1849 at various points in the movie.

“We have Asians playing Caucasians, men playing women and women playing men,” Kennedy says. “If we stayed specific to ethnicity, we would never have been able to cast the movie that we did.”

The actors relished the chance to play roles way outside their usual types, she adds, citing a certain actor known for performances in contempo romantic comedies as one example.

“Hugh Grant would never get cast as a Maori warrior.”

Eye on the Oscars: Talent Race
What’s their damage? Plenty | Thesps weigh reel-life choice | Great performances in genre movies | Minors show their pluck in grownup fare | Seniors grab center stage | Roles all over the map in this ‘Atlas’ | Repeat contenders