3. Finding The Grouch

“I did a really early drawing of this grouchy guy with these colourful, happy, fun balloons, smiling and stuff,” Docter told Moviehole, "and I just thought he really contrasted that.”

Many influences seem to have been poured into Carl – Spencer Tracy and Walter Matthau were among the actors that the team studied, and they also watched home-movie footage and brought stories about their own grandparents together.

"Bob and I just sat in a room and started throwing ideas out,” recalls Docter. “Like, ‘What interests you? What elements would make a good film?’. And a crusty, grouchy old man really feels appealing to me and to Bob. We just felt like there was a lot of entertainment possibility there.

"There’s a rich history of grouchy old men characters - just look at the George Booth cartoons in the New Yorker.”

Another inspiration was classic Disney animator Joe Grant, who consulted on the script and helped solidify what old folk could get away with for Docter.

"He has this charm and this 'old man license' to say things that other people couldn’t get away with,” says the director. “It's like how we would go to eat with Joe Grant and he would call the waitresses 'honey'. I wish I could call a waitress 'honey'.”

With a main character in mind, and a story formulating about the nature of Carl's adventure, Docter and co needed to do some on-the-spot research. Time to travel…

Next: Field Trip