Peter Jackson, Fran Walsh, and Phillipa Boyens wrote the screenplay for The Lord of the Rings trilogy, and Peter Jackson directed it. There were many people involved in the creation of the movies, not just the screen writers; the actors, the huge support staff, everyone involved helped create the vision for the movies. Because he has been the major spokesperson for the trio and has had, in many ways, the definitive vision for Middle Earth, I will simply say "Peter Jackson", and you will understand that Phillipa and Fran were vital in the writing, interpretation, and creation of the movies, please.
The Lord of the Rings trilogy began filming in 1999, and the movies came out in 2001, 2002, and 2003. Peter Jackson, at that time, was asked if he would make The Hobbit into a movie. His answer, an unqualified no, was a reflection of the sheer amount of work it was to make LotR, no matter how much fun and pleasure he got out of it. "Never again..."
A few years later, though, he and his LotR co-writers joined with Guillermo del Toro in writing a screenplay for The Hobbit. Writing a screenplay is vastly different from directing a movie, however, and Guillermo was slated to direct it. Difficulties in financing the movie (millions of dollars were at stake and needed to be funded), problems regarding the book's movie rights, and other issues all caused delay after delay in the film's production. There was no 'green light' for funding and such necessities. In the meantime, work continued on the screenplay. Jackson and his two LotR co-writers already had a definite vision and feel of Middle Earth, and Guillermo was able, with them, to take that and build upon what was already there.
Delay after delay later, though, Guillermo finally stepped out of the project; he had other projects he wanted to do. So there was the screenplay, basically written, and no director. Jackson did not want to direct it; he knew that directing another tremendously involved movie would be stressful, tiring, and... he didn't want to do it! He had wanted Guillermo to direct it, and already del Toro had begun creating his own vision of The Hobbit with the technicians and model-makers and everyone who was already working on the building the movie.
The crunch came; casting needed to happen, and the movie had no director. Peter Jackson had finally fallen back in love with the story, as well as the screenplay. Also, he said in one of the commentaries that he had his own vision of Middle Earth (from making LotR) and wanted to continue it as it was and not have someone else come in, imposing a whole different flavour upon The Hobbit movie. So he agreed to direct the movie, and casting could start.
There is so much in the making of the film that I'm going to be leaving out. Just know that, okay? I'm going to be focusing on just a few aspects of how The Hobbit movies were made.
First off, one of the difficulties of bringing The Hobbit to the screen was the dwarves; there are thirteen of them. That is fine in a book; Professor Tolkien could say 'the dwarves', and it worked just fine. Also, this was a book for children. An in-depth character study of each of the thirteen dwarves was not necessary; this book was about a hobbit — a hobbit who went on an adventure!
But for a movie, that would not work. Sure, the character of the Hobbit would be important, but for a movie, each dwarf would have to have their own personality, their own unique characteristics. So in addition to coming up with a story, each of the dwarves (who Professor Tolkien named and also gave a few of them some characteristics and traits) needed to be identifiable by the audience. Who was Thorin? Who was Gloin? If the audience didn't understand them as individuals, the movie as a whole would flop. So, the casting was vital because Jackson decided that each actor would be partially responsible for coming up with their own dwarf.
The casting for the dwarves ended up being brilliant. The actors are incredible. They went to Dwarf Boot Camp months before filming started so they could get in condition for the strenuous physical exertion they would be encountering. They had to learn to move like dwarves — not with the lilting step of humans but with a low, earthbound, horizontal motion. They gained a familiarity, if not an expertise, with weapons, horseback riding, and basic gymnastics. Then they acquired their dwarf outfits — oversized costumes and prosthetics — to keep them looking like dwarves and not just hobbits (or even children) when they were seen on screen. (Because dwarves are approximately the height of hobbits, who are, after all, very short people, there was a lot of digital character resizing involved in the film.)
Richard Armitage, who played Thorin Oakenshield, said, "It was literally boot camp because part of it was learning to run in these incredibly heavy boots they had designed for us. In order to make the dwarfs [sic] really heavy and warrior-like, they increased the size of our feet and our hands and our heads. It was a little bit like having concrete in your shoes and also wearing a diaper." (1)
It was difficult learning to manipulate such simple things as pipes, forks, or weapons with prosthetics on their hands to make them look larger, but they succeeded in learning how to be dwarves rather than actors playing dwarves.
The Hobbit himself, Bilbo Baggins, is played by Martin Freeman. He joined the Dwarf Boot Camp, even though as a hobbit he would not be expected to look like he could run (or work) all day and then sit down to a hearty dinner. However, he also knew that he would want and need to keep up with the demands of the movie, and this would be a great way to bond with the other actors.
The bonding during Boot Camp was great, and the result of this careful planning on the part of the director and gang reflected greatly in their first scenes together: the infamous gathering at Bag End, the book's "An Unexpected Party."
We can't forget Gandalf! Yes, Gandalf returned from LotR, with Sir Ian McKellen reprising the role. His persona had already been crafted in the LotR movies, and all it took was a little time for Sir Ian to reacquaint himself with the Gandalf the Grey. (Other familiar faces from LotR appear in the movies; we will talk about that in later lessons).
(1) https://web.archive.org/web/20180716165621/http://herocomplex.latimes.com/movies/the-hobbit-richard-armitage-finds-thorin-oakenshield-in-macbeth/#/0