An average inch of hair weighs about 50 µg - a light estimate, as blonde hair tends to be lighter than other colors. Animators have said that Rapunzel's hair is approximately 70 feet (840 inches), and consists of about 100,000 strands. That yields 4,200,000,000 µg = 4,200,000 mg = 4,200 g = 4.2 kg (approx 10.4 lbs) of hair. We assume that its manageable weight in the movie is another innate magical property.
The character design of Flynn came from the process which was called the 'hot man meeting' by Nathan Greno and Byron Howard, during which they set up a meeting with all of the female employees of the studio in one room and asked them for their opinions of what made a man good looking in order to create Flynn's character design with features such as eye color, hair color and style and body type. Video footage showed concept art and photos of various male celebrities, including Johnny Depp, Hugh Jackman, Brad Pitt, David Beckham and Gene Kelly on the walls of the room.
For the scene in which Rapunzel enters the marketplace, animators were inspired by entrances of Walt Disney World and Disney Land. Rapunzel's excitement towards all the music and people is reminiscent of children at the parks.
Gothel's dress is from the Renaissance, which is centuries before the time period of the film (the 1780s). This is an effort to emphasize how Gothel and Rapunzel don't match up and how long Gothel had been living.
Disney's previous animated feature The Princess and the Frog (2009), despite being popular with critics and audiences alike, was a box office disappointment. Disney felt that the film's princess theme discouraged young boys from seeing it. In an attempt to market the film to a broader audience, Disney changed the title of the film from Rapunzel to Tangled, and promoted it as a comedic adventure. An early trailer for the film focused less on Princess Rapunzel and more on Flynn Rider, the male lead character. It was originally believed that Disney's marketing campaign was a desperate attempt to search for a particular audience. However, Byron Howard and Nathan Greno, claimed that the title change was to emphasize that Flynn has as much of a role in the film as Rapunzel.
In the marketplace, when Rapunzel looks at the mosaic of herself, the camera cuts from her eyes to the tile eyes of the picture and - very briefly - there is a clarinet musical motif that is exactly the same as the motif in Ferris Bueller's Day Off (1986), when Cameron is looking at the pointillist painting and the camera cuts between Cameron's eyes and that of the child in the painting. The moment is just a fraction of a second; just after that, Rapunzel looks at the clarinet player walking behind her and smiles.
The teaser trailer for the movie showed the first meeting between Rapunzel and Flynn quite differently. After hitting him with the pan, Flynn comes to but Rapunzel stays out of sight, while her hair punches and grabs him, and drags him around the room in slapstick fashion. When Flynn is tied to the chair and tries his smoldering look on her, she throws him out of the tower while still tied to her hair. There is also an unused scene where Flynn waits at the foot of the tower and gets the full weight of Rapunzel's hair thrown on him, which greatly amuses Maximus the horse.
According to Glen Keane, the movie's visual style (a three-dimensional painting) was greatly inspired by the Romantic painting "The Swing", by the French rococo artist Jean-Honoré Fragonard: "A fairy tale world has to feel romantic and lush, very painterly." For a clear idea of what was intended, the animators duplicated the picture in 3D to achieve a shot containing depth and dimensions.
The sword that Maximus uses to fight Flynn at the dam is a Roman gladius. This would normally be an anachronism to the time-set of the movie. However, in this case it is very fitting because the name Maximus is also a Roman name.
In addition to finding Pinocchio in the Snuggly Duckling, you'll also find Pumbaa from The Lion King (1994) (visible in the same scene as Pinocchio with the "cupid" swinging) and Louis from The Princess and the Frog (2009) (one of the puppets used later in the song). It can be inferred that they're all involved in this scene due to them all having dreams (Pinocchio=real boy, Pumbaa=accepted despite bad gas, Louis=jazz musician).
Glen Keane credits animator Kyle Strawitz for achieving the painterly style of the film: "Kyle helped us get that Fragonard look of the girl on the swing... He took the house from Snow White and the Seven Dwarfs (1937) and built it in CGI, and painted it so that it looked like a flat painting that suddenly started to move, and it had dimension and kept all of the soft, round curves of the brushstrokes of watercolor. Kyle really helped me start to believe that the things I wanted to see were possible... that you could move in a Disney painterly world."
According to production manager Doeri Welch Greiner, the original script was a quasi-sequel to Enchanted (2007), and had Rapunzel turned into a squirrel and her place taken by a girl in the real world. Glen Keane eschewed in favour of a more fun and fantastical fairytale that Disney is famous for: "I think that's what Disney needs to do right now. No one else can do it. We should not be embarrassed or make excuses for doing a fairytale."
From the beginning, Glen Keane intended that the film looked and felt like a traditional hand-drawn film, but in 3D. He hosted a seminar called "The Best of Both Worlds," where he brought in 50 Disney animators (both CGI and traditional artists) to discuss the techniques used in each style and how to, in his words, "bring the warmth and intuitive feel of the hand-drawn to CGI."
The algorithm that manages how Rapunzel's hair moves appears to be based on a similar algorithm for cloth. This is noticeable, for example, at the end of the "When Will My Life Begin" montage as she tosses her hair around her in a spiral.
In the Snuggly Duckling tavern, the ruffian 'Greno' who leaves to get the guards is named for and modeled after the film's co-director Nathan Greno, only much bigger but with the same van Dyke-style goatee and the same arm tattoos.
According to Glen Keane, the technique of non-photorealistic rendering was extensively used to make the CGI surface look like it is painted but still containing depth and dimension. He also mentioned the use of subsurface scattering and global illumination and "all of the latest techniques" to render, in computer-generated imagery, convincing human characters and rich environments.
The lantern that Mother Gothel holds during the line "the plague" in the song "Mother Knows Best", and in the beginning when she is singing to the flower, is the same lantern the Stabbington brother's hold when Flynn sees them across the water.
Glen Keane's ambition with this film, technically speaking, is to make the computer "bend its knee to the artist" instead of having the computer dictate the artistic style/look of the film, and make the computer become as "pliable as the pencil."
The trivia items below may give away important plot points.
In the opening scenes you see baby Rapunzel in her cradle staring up at a baby mobile. In a little bit of foreshadowing, you see several items hanging from the mobile that come into play later in the story, namely a chameleon (her pet Pascal), a rubber ducky (The Snuggly Duckling that Flynn takes her to), a cupid (also from the Snuggly Duckling), a horse (Maximus) and a blue bird (when she first leaves the tower).
While it may seem that Mother Gothel is the eighth animated Disney villain to fall to her death - following the Wicked Queen (Snow White and the Seven Dwarfs (1937)), Ratigan (The Great Mouse Detective (1986)), McLeach (The Rescuers Down Under (1990)), Gaston (Beauty and the Beast (1991)), Frollo (The Hunchback of Notre Dame (1996)), Queen Narissa (Enchanted (2007)), and Charles Muntz (Up (2009)) - she does not in fact die in this manner. She is, however, the only Disney villain to die from extreme and rapid old age - brought on by the sudden loss of the magic effect on her of Rapunzel's blonde hair. She only happened to be falling out of a 70-foot window at the time; once her cloak hits the ground, she has already turned to dust.
Rapunzel's hair color in the film (blonde as a child, but returned to its natural brown as an adult after the magic was taken from it) mirrors that of her portrayer Mandy Moore, who broke into the public light as a blonde teen singer, but has since become known with her natural brown hair.