Paterson said it was very important for him to keep the spirit of the book alive. At the same time, he had to change it from "a novel that takes place mostly in the characters' heads to a dynamic visual medium". Paterson knew that the movie had to be about friendship and imagination. He focused "bringing out the emotions of the story." He said he found it difficult to write about Terabithia. This was "because it was too close". He credited fellow screenwriter Jeff Stockwell for recreating Terabithia for the movie. "What Jeff was able to do as an outsider who wasn’t so attached to the story was to really let his imagination go free and make up this world in a wonderful way", David said. Csupó said that the two main characters are a little bit older in the movie. Csupó claims the movie "deals with so many issues including friendship, and maybe first innocent love, things like that", so it "made more sense" to make the characters older.