For such a massive production that took about a year-and-a-half to finish, Marvel Studios enlisted the help of nearly every major VFX house in the world for Avengers: Infinity War, as the movie has almost 3,000 VFX shots.
One of them was Weta Digital, co-founded by Peter Jackson and named after the massive crickets found in New Zealand. Weta, under the direction of Matt Aitken, found itself responsible for the scenes on Titan, the look of Thanos (Josh Brolin), Doctor Strange's magical abilities, Peter Parker's Iron Spider legs (Tom Holland was totally CGI from the neck down), and, saddest of all, the disintegration effect caused by the Gauntlet snap.
Check out Weta's VFX reel below:
The vanishing effect of the Infinity Gauntlet at the end of the film, dubbed the "blip," was meant to have as much shock value as possible, both on the characters and audience. On that front, Weta succeeded and then some by creating what Aitken called "complex growth algorithms" during an interview with io9.
"Early on in our involvement with the project, Marvel asked us to develop a concept for what the blip might look like," he said. "Part of the brief from the Russo Brothers was that the effect had to look final, like there was no coming back from it. They also wanted it to look painful with a component that was quite violent, they didn’t want it to be too gentle or lyrical."
Drax was the first test subject because of his natural baldness. "We wanted to hold off on developing the hair component of the blip until we had the rest of the effect somewhat in place," Aitken continued.
One of the more difficult set pieces to pull off was the much talked about moment when Thanos uses the Gauntlet to rip a moon straight out of Titan's atmosphere and throw it at the Avengers. (According to Joe Russo on the Blu-ray directors' commentary, two of the Infinity Stones accomplished this: the Power Stone destroys the moon, while the Space Stone to pull it down.)
"The challenge in creating the sequence where Thanos destroys a moon and pulls it down on Iron Man and the Guardians was the huge scale of the event: the Russos referred to this sequence as a ‘global destruction’ event," Aitken told io9, "and the atmosphere on Titan is filled with dust and debris for the rest of the movie."