Pixar has been no stranger to major, last-minute changes on its films—especially when it comes to swapping out the director—but changes for the studio’s upcoming The Good Dinosaur has had quite possibly the farthest reaching effect.  Up co-director Bob Peterson was poised to make his directorial debut with the film, but he was removed from the project nine months before release.  The film was subsequently pushed back from 2014 to November 25, 2015, leaving Pixar without a 2014 release and straining the studio financially, resulting in layoffs and a shift of the Finding Nemo sequel Finding Dory to 2016.

The studio confirmed last month that Peterson’s co-director Peter Sohn has now taken over as the director of the film, and details have surfaced regarding how Sohn overhauled the story and why Peterson was fired in the first place.  Read on after the jump.

For those unaware, the central story nugget of The Good Dinosaur imagines a world in which the asteroid never hit the earth, leaving the dinosaurs to co-exist with humans hundreds of years later.  That central premise remains intact in the new version of the film, but per the LA Times, Sohn axed some of Peterson’s central ideas like modeling the dinosaurs on Amish farmers, and added new elements like treating nature as the film’s antagonist:

"When Bob was taken off, I was supporting the film as best I could," Sohn said. "It felt like, this child, this film still needs to be raised. It was just about how to take care of the thing at that time. ... Trying to keep the original vision of this film intact and trying to plus it as well."

The film is described as a buddy comedy between a teenage dinosaur named Arlo and a wild human boy named Spot, who serves as Arlo’s pet.  Peterson ended up being removed from the project when the Pixar leadership felt he was “creatively stuck on the film and was proving too slow to make important story decisions.”  Peterson remains an employee at Pixar, however, and has been working on Up director Pete Docter’s next film Inside Out and also writing on Finding Dory.

Sohn was given the job of director last summer after pitching his new version of the film via storyboards to producer Denise Ream (Cars 2), but Pixar has surrounded the first-time filmmaker with some veterans of the studio to smooth the transition.

Given The Good Dinosaur’s well-publicized issues, I imagine many are curious to see how the finished film turns out.  Pixar normally has a good track record with projects that have trouble in development (Ratatouille, Toy Story 2), but recent director changes on films like Cars 2 and Brave have resulted in less-than-stellar features.  Next summer’s Inside Out looks incredibly promising, so here’s hoping the new version of The Good Dinosaur holds up to the studio's high standard as well.