These days in Hollywood filmmaking CGI is a regular part of the lexicon. The technology has become so advanced that we don't even notice its being used anymore, even when a movie is being crafted completely through the use of CGI like the live action Jungle Book movie. The Star Wars franchise obviously uses quite a bit of CGI, which J.J. Abrams coupled with practical effects for The Force Awakens. This was a welcome change in the completely green screen environment created in the prequels, but now it appears that CGI was used in some unexpected places in The Force Awakens.

In preparation for the release of the 3-D/Deluxe version of Star Wars: The Force Awakens, clips including J.J. Abrams' personal commentary have slowly been released. In this commentary, Abrams revealed (via io9) that the first scene between Kylo Ren and Snoke included CGI being used in a tricky way, saying:

In this scene we originally shot Adam Driver with his mask off, that he had his first scene with Snoke with his mask off. And we ended up putting it on in post. So the mask you see in this shot is actually a CG mask that was added later.

Literally no one saw this coming. No matter what eagle eye for CGI you have, there's no way that you could tell that Kylo Ren's signature helmet was put on in post. Way to go, visual effects team.

Kylo Ren's relationship with his signature mask has been a somewhat controversial subject for hardcore Star Wars fans. Many believed that seeing Kylo Ren without his mask on ruined the villainy and mystery of the character. During the original trilogy, fans were left to their own imagination when it came to Darth Vader's face. His masked stayed on for almost the entirety of the movies, with Luke only removing it during the tail end of Return of the Jedi. This added to the mystique of the character, and made the reveal even more satisfying.

Kyo Ren, however, removed his mask about two thirds into the events of The Force Awakens. The terrifying and powerful sith was suddenly reduced to a normal angsty young man, as he attempted to probe Rey's mind for the location of BB-8. From then on, we mostly saw Ben Solo without his mask, and the villain remained a flawed and thoroughly human character. While this made his final conflict with Rey more interesting, and surely added emotional weight to the death of Han Solo, it also ruined the mystery and menacing nature of the Star Wars villain.

So while many fans argued that Kylo Ren's mask was taken off too early, it now appears that he originally took it off even earlier in the film. But J.J. Abrams seems to have anticipated fan outcry, and used clever visual effects to keep the mask on for a bit longer.