Since Star Wars: The Last Jedi came out, there have been some questions as to whether the Force projection ability used by Rey, Kylo Ren and Luke Skywalker is actually canon. Director Rian Johnson has attempted to finally put these concerns to rest on Twitter by pulling from 2010 book The Jedi Path: A Manual for Students of the Force, a real-life tome meant to mirror an in-universe Jedi Order guidebook.
Under the "Advanced Force Techniques" chapter, Johnson shows an ability called Doppelganger or Similfuturus, which bears an uncanny resemblance to what was shown in the film. The passage from the book reads as follows:
"Doppelganger or Similfuturus permits a Jedi to create a short-lived duplicate of himself or herself or an external object that is visually indistinguishable from the realm item. Those who have perfected this ability can create phantoms of any person of their choosing or trick an enemy into seeing more objects, such as droids, than are actually present."
Despite the criticisms Johnson has received for this specific use of the Force, it's clear that he didn't make it up on the spot. The Force projection has firm footing in the Star Wars universe. Furthermore, the description in the book states that users can also project objects instead of people. This would explain how Luke was also able to project the dice he found in the Millennium Falcon.
Johnson has already defended his use of the Force projection once before, but now that it's backed up with a canonical source, it's a different challenge for detractors to argue against it. This could lead to the power returning in a future Star Wars movie, especially considering that Rey and Kylo were using a smaller-scale version of it to communicate with each other, but only time will tell. For now, it's at least clear that Luke's Force projection has been a part of Star Wars canon before The Last Jedi even began production.
Directed by Rian Johnson, Star Wars: The Last Jedi stars Daisy Ridley as Rey, Jon Boyega as Finn, Adam Driver as Kylo Ren, Oscar Isaac as Poe Dameron, Carrie Fisher as General Leia, Mark Hamill as Luke Skywalker, Andy Serkis as Supreme Leader Snoke, Benicio Del Toro as DJ, Laura Dern as Admiral Holdo, Kelly Marie Tran as Rose, Domhnall Gleeson as General Hux, and Gwendoline Christie as Captain Phasma.