Bella's body was prosthetic from the shoulders down in the birthing scene. There was an opening in the table so Kristen Stewart could comfortably lay down underneath the table top while still allowing her head and shoulders to be visible. To achieve movement of the prosthetic limbs a puppeteer was also under the table controlling the limbs.
It took three hours to apply all the necessary make-up effects to Kristen Stewart to create Bella's emaciated physical appearance. Effects that couldn't be achieved with make-up were created digitally in post-production.
During their vows and first kiss as husband and wife, the song "Flightless Bird, American Mouth" by Iron & Wine plays. This is the same song they danced to at the prom at the end of the first Twilight (2008) installment when Bella first tries to convince Edward to turn her so they can be together forever.
Kristen Stewart has said in an interview that filming Bella and Edward's honeymoon sex scene was very awkward, and that by the end of the shoot, she didn't even feel like they had just filmed a passionate scene.
On the third day of filming in Brazil the cast and crew got stranded overnight on the island location used for Isle Esme due to a severe rain storm. The crew had to cover the furniture and props in the house with tarps to prevent water damage due to the rain and people having wet clothes.
In 2012, author Stephenie Meyer told Entertainment Weekly magazine that while she was filming her cameo in the wedding scene, she sat next to producer Wyck Godfrey, who was also appearing in the scene as a wedding guest extra. Meyer said that she and Godfrey spent their time creating a backstory for their "characters": that Godfrey "was a deputy policeman, and our marriage was on the rocks because he was in love with [Bella's father] Charlie."
Costume designer Michael Wilkinson worked closely with Ashley Greene to design Alice's dress worn at the wedding. They decided on a flapper-like dress to reflect her native time period of the 1920s. Wilkinson also worked closely with Nikki Reed to create Rosalie's dress.
Is the first Twilight film in which Stephenie Meyer served as a producer and is credited as one. Although Meyer was present on set during the previous three films she never officially held the title of producer.
Similar to the book, the film briefly shifts from Bella's point of view to Jacob's. Director Bill Condon commended Taylor Lautner for pushing himself to dig into Jacob's character more to show his side of the story.
Director Bill Condon reveals in the DVD commentary that the Isle Esme house had to be recreated on a sound stage in Baton Rouge, Louisiana due to production only having one week on location in Brazil. Most of the indoor honeymoon scenes were shot on the sound stage in Louisiana and not in Brazil.
Was filmed back to back with The Twilight Saga: Breaking Dawn - Part 2 (2012). Filming began on November 1, 2010 and wrapped on April 15, 2011. They were filmed on location in Vancouver, Rio de Janeiro, and Baton Rouge.
One of the key elements in both the book and the movie was is how Edward tries to distract Bella with activities in order to keep her from thinking about having sex again. In the movie, one of the activities is a game of chess, with both red and white pieces, just like the pieces on the cover of the book.
Takes place in a period of one full month. The Twilight character guide points out that Renesmee's birthday is 11 September, thus at the film's cliffhanger scene, it takes place the next morning (12 September).
Bill Condon chose not to show Edward ripping Bella's body open with his teeth during the childbirth because he felt having the audience experience it via sound effects and having Robert Pattinson slightly out of frame made it more potent. He also felt it made the scene more special for viewers who have read the book.
To achieve the effect of a newborn Renesmee, the visual effects team used the motions of over 30 real babies using the Lola projection rig. Small bits and pieces were taken to create the final look. Images of Kristen Stewart were also used so the baby would most resemble her like in the book.
Director Bill Condon specifies that Bella's walk down the aisle during the wedding scene was shot through her point of view thus giving it the longer time frame. He thought the walk would feel long to Bella so he incorporated that into the film so the audience could feel what she would be feeling.
The visual effects team used a Lola projection rig to age Mackenzie Foy during the imprinting scene. They used footage of an 18-year old model running and digitally aged a CyberScan of Foy, then 10-years old, to match the model's mannerisms. The team used similar software that companies use to age and locate missing children.
At Esme Island, Bella's chess pieces while she's playing are white in color, foreshadowing her character's transition towards the start of The Twilight Saga: Breaking Dawn - Part 2 (2012). The transition was also related by Stephenie Meyer in regards to the theme of the book's cover (red pawn, white queen).