Warning: There are major spoilers ahead for "Star Wars: The Rise of Skywalker."Insider spoke with some of the visual effects team at Industrial Light & Magic behind the latest "Star Wars" movie.Visual effects supervisors Patrick Tubach and Roger Guyett shared what went into bringing Rey's two lightsabers to life, how Carrie Fisher's appearance in the movie was made possible, and more.Insider also rounded up a few other details on the making of the film.Visit INSIDER's homepage for more stories.Rey's staff is the hilt on her new lightsaber.This may have been an easy one to miss, but Rey's staff is now an integral part of her lightsaber."That was the concept," "TROS" visual effects supervisor Roger Guyett told Insider of the inspiration behind using Rey's staff as a part of her lightsaber."The art production design and the art department, we all contribute to the designs of various things... [director] J.J. [Abrams] just thought it was logical that she had the staff, and, therefore, the saber should somehow be linked to that," Guyett added.The visual effects team refer to the color of Rey's new lightsaber as "yellow optimism."Guyett told Insider they discussed and ran tests on what color Rey's lightsaber at the film's end should be before landing on the yellow-orange hue we see on screen.Guyett and ILM visual effects supervisor Patrick Tubach both described optimism as an inspiration behind the yellow color we see."I'm going to paint my house 'yellow optimism,'" joked creature and makeup effects creative supervisor Neal Scanlan.In case there was any doubt, Rey's yellow saber contains a yellow kyber crystal.We thought it would have been a nice touch if Rey's lightsaber contained a healed version of Kylo Ren's cracked red kyber crystal, but the VFX team dashed our "Star Wars" fan-fiction."Yeah, it's supposed to be a yellow crystal," Industrial Light & Magic (ILM) visual effects supervisor Patrick Tubach told Insider.Where did Rey acquire that yellow crystal' Unclear. It's not like kyber crystals are lying around.You can read more about the making of Rey's lightsaber here.Rey's red lightsaber took some inspiration from Darth Maul and Kylo Ren's three-pronged lightsaber."Clearly you've got the Darth Maul connecting but there's also a mechanical aspect to it and don't you think she looked fantastic in that moment'" said Guyett, comparing Dark Rey's lightsaber to Darth Maul's double-bladed saber from "The Phantom Menace.""I think the mechanical aspect of that lightsaber gave it that great quality of upping the ante. When it switches out, there's some kind of Jedi-ish or samurai sword-ish kind of feeling," added Guyett who said the fight scene between the two versions of Rey was developed after director J.J. Abrams saw Ridley in the dark Rey costume.Visual effects supervisor Patrick Tubach added that Kylo Ren's lightsaber also came up in conversation as inspiration for the look of dark Rey's blade."On [Episode] 'VII,' it was a really great design choice when we started working on Kylo's lightsaber to say, 'What almost looks like a broken light tip'' or 'What looks so angry [that] someone put it together in anger''" said Tubach."I think that made sense to take that same look," Tubach said of what the team did with dark Rey's saber. "We asked J.J., 'Is this looking more like an in-control saber' Or is this more of an angry kind of saber'' He definitely felt like we needed to show 'this is a dark, dark saber.' So that look of that fiery edge and everything, we kept some of that same aspect of Kylo's saber in this one."The VFX team changed up Daisy Ridley's teeth for the dark Rey reveal.When Dark Rey opens her mouth, you may have jumped back a little because she had some scary, sharp teeth to show off."She looked normal then she did the gesture at nice Rey, and she revealed that her teeth had changed. So it was something that we did afterward," said Guyett, confirming that Ridley wasn't wearing fake teeth while filming that scene.If you're a big "Star Wars" fan, you know that if you venture to the dark side of the Force, it will start to change your appearance. It looks like that's what happened with Rey in this scene.General Leia Organa was brought to life by having Carrie Fisher's face placed on a digital character."When you see Leia in 'Episode IX,' basically it's a live-action element of her face with a completely digital character," said Guyett of how Carrie Fisher is in "TROS."This was done because they wanted to ensure Leia had a distinctly new look from the previous two films."The reality of doing this is that you want her to have a new costume," said Guyett. "It would be weird if she just looked like she did in 'Episode VII' or 'Episode VIII.' You want her to have a new hairstyle because she's very specifically part of 'IX.' So we knew that we were going to have to do all of that."A stand-in played Fisher on set for the actors to interact with."We had a fantastic stand-in for Princess Leia who looked at all the footage and tried to learn the lines and represent Carrie as best as possible so that if you're acting against her you're not just looking at an empty space, you're looking at a human being who's delivering the line," said Guyett.Scanlan said the stand-in had her hair and makeup done to match Leia.You can read more about how Fisher was brought to life in "TROS" here.Carrie Fisher's daughter, Billie Lourd, plays her mother in the flashback scene with Luke Skywalker.In a small moment, a young Luke Skywalker, played by Mark Hamill, trains his sister as a Jedi.Tubach told Yahoo Entertainment Leia is a combination of Carrie Fisher images from "Star Wars: Episode VIReturn of the Jedi" and Fisher's daughter Lourd."It was a poignant thing, and something that nobody took lightlythat she was willing to stand in for her mom," said Tubach.There's a moment from the first "Star Wars" movie referenced near the film's end."One small nugget that somebody may not have picked up on is that as you fly up through that giant lightning tree and you get up to that top of the tree and she hears the voices of the Jedi, that starfield you're looking at is exactly the 'Episode IV' starfield," Tubach told Insider of the moment right before Rey hears the voices of the Jedi."That was very important to J.J. [Abrams]," he added. "He really wanted to have that moment harking back to the very beginning of 'Star Wars,' and that I think was bringing it all back together. Seeing those stars and seeing them look exactly that way. It does rotate, but what you end up on is in the beginning of 'Episode IV.'"We were never going to get Force ghosts when Rey hears the Jedi of the past."I think we talked about that at one stage," Guyett told Insider of whether or not they discussed putting Force ghosts into the scene where Rey hears former Jedi, including Qui-Gon Jinn (Liam Neeson), Anakin Skywalker (Hayden Christensen), Mace Windu (Samuel L. Jackson), and more."What I liked about that idea as it developed was that you feel like you're with Rey and you're inside her head," Guyett said. "Of course, it's very subjective about what may or may not feel right for that moment, but what we were trying to capture was that it was happening to her inside her head by using voices rather than physical representations of those people within that space."There were also no plans for former Sith lords to appear in the giant stadium scene.As Rey and Palpatine prepare to do battle, we see them surrounded by a stadium filled with mysterious, cloaked supporters."I think the notion is that those are Sith loyalists within that arena and that they were, in some ways, more anonymous in their part in that particular process," Guyett said of the scene retaining the focus on Palpatine and Rey."They were loyalists and I don't remember any great desire to be overly specific about who they were in that group," he added. Click here to read full news..