SEATTLE — “Shrek the Musical,” which opened here Sept. 10 in its pre-Broadway engagement, has been percolating for five years, including three readings, a seven-week workshop and a month of previews.

That lengthy development process — spearheaded by DreamWorks Theatrical prexy Bill Damaschke (also co-prexy of production at DW Animation) and Caro Newling of Neal Street Prods. (Sam Mendes’ production company) — has earned the team a rep as tough perfectionists.

But that doesn’t mean the work is over.

Throughout the process, the “Shrek” gang, particularly Damaschke and DreamWorks co-founder Jeffrey Katzenberg, have become unstinting critics and collaborators, prompting rewrites, redesigns and rethinks.

During development, “C.B.B.” has become the shorthand for elements that Could Be Better.

“The thing that I think has been best for the show has been the rigor with which Bill and Jeffrey develop the material,” says Newling. “But it’s not about corporate and employee. It’s about how we could do this better.”

Producers aren’t fessing up to capitalization costs, but the show is said to ring in north of $20 million.

After playing to an enthusiastic opening-night crowd, mixed reviews from Seattle press began to make their way online. Critics (and some Gothamites here) said the story has plenty of heart — an asset boosted by strong lead perfs — but kinks remain to be worked through.

During the Seattle run so far, a few songs have been cut and others added, with more work on the way.

Meanwhile, the show’s new logo was recently unveiled, dropping a preliminary image of a gooey S in favor of a more rustic font that stands further apart from the movie’s brand identity.

By the time the show hits New York’s Broadway Theater Dec. 14, there will be significantly redesigned costumes for two major characters, Donkey and the Dragon (currently represented by a confusing amalgam of a giant puppet and nine actresses).

And in recent weeks, choreographer-helmer Rob Ashford (“Curtains”) has come aboard as an unbilled consultant.

“Rob has a lot of experience with musical staging,” Damaschke says. “We felt like a fresh look at all the numbers would be great.”

As DreamWorks seeks to craft an identity distinct from well-established competitor Disney Theatrical Prods., “Shrek” producers will attempt to define both the production and the budding legit org that has a library of titles to tap should the tuner prove a success.

Based on DWA’s 2001 pic and the William Steig children’s book that inspired it, “Shrek” hit cinemas without original songs already in place, despite strategic use of music from Smash Mouth and the Proclaimers.

Aiming to avoid the perception of creating a theme park show, DreamWorks Theatricals assembled a “Shrek” creative team that surprised legiters with its credentials. The book and lyrics are by David Lindsay-Abaire, who picked up the Pulitzer in 2007 for his play “Rabbit Hole,” with tunes by Jeanine Tesori, the “Thoroughly Modern Millie” composer whose last Broadway outing was the musically ambitious “Caroline, or Change.”

Jason Moore (“Avenue Q”) directs a heavy-hitting cast of Rialto regulars led by Brian d’Arcy James, Sutton Foster and Christopher Sieber.

The show has a large-scale, complicated set and costume design by Tim Hatley (“Monty Python’s Spamalot”), with pricey components like a master turntable containing two other turntables that rotate and rise separately; a dragon that breaks through a giant stained-glass window; and the Shrek costume’s complicated prosthetics, many of which can only be used for a single perf before being replaced.

DreamWorks and Neal Street, connected through Mendes’ movie output for the studio (“American Beauty,” “Road to Perdition”), began talks about “Shrek” in 2003.

As is always the case with adaptations of well-known pics, part of the creative challenge is how far afield to wander from the title that inspired it.

Initial discussions imagined the ogre in a meta-comedy set in the world of musicals. But while the stage version of “Shrek” does include the movie’s anachronistic sense of humor — including, at least in Seattle, a couple of digs at Disney Theatrical shows — it was ultimately decided to stick to a familiar narrative route.

“One of the things you’re managing is expectations,” says Moore, who, like Lindsay-Abaire, was one of the first members to join the creative team.

Along with creative fine-tuning, there’s the added challenge for DreamWorks of being a studio muscling in on Rialto turf. And it’s up for debate whether such a venture has become easier or more difficult in the nearly 15 years since Disney took to the boards.

With “The Lion King,” Disney proved a musical based on an animated pic could garner both critical and box office validation. But in recent years, Broadway also has been bombarded with film-inspired tuners that didn’t deliver.

Burned by past experiences with large-scale productions that failed to live up to the hype, many group sales auds seemed to be holding off on buying “Shrek” tickets until Seattle reviews hit. And Gotham critics may well be predisposed to approach another cartoon-onstage with ogre-like grumpiness.

That context helps explain DreamWorks’ unhurried approach to the undertaking.

As for what’s next for the org’s stage output, no plans have been set, although Damaschke can envision some sort of live event — not a musical — based on “Kung Fu Panda.” Plus, the DWA library also boasts the 1998 pic “The Prince of Egypt,” which, with a score by Stephen Schwartz , regularly attracts interest from legiters.

“I get a call once a week about that one, ” Damaschke says.