In the 1960s, Mr. Cantwell was a contract worker for NASA’s Jet Propulsion Laboratory, developing programs to educate the public about early space missions, and for Graphic Films in Los Angeles, which made live-action and animated films for NASA, the U.S. Air Force and industry clients. Douglas Trumbull, who died this year, had worked at Graphic Films before being hired by the director Stanley Kubrick for “2001.”
Mr. Trumbull became a special photographic effects supervisor on “2001,” and Mr. Cantwell joined the crew from Graphic Films in 1967, during the last six months of its production. He organized 24-hour shifts of animation to complete the film’s animation, according to “Space Odyssey: Stanley Kubrick, Arthur C. Clarke, and the Making of a Masterpiece” (2018), by Michael Benson. Mr. Cantwell also produced some of the movie’s space sequences, suggested different camera angles to depict the arrival of a shuttle on the film’s space station, and worked with Mr. Trumbull to depict Jupiter’s moons.
And, Mr. Benson wrote, Mr. Cantwell’s conversations with Kubrick about Ingmar Bergman’s filmmaking led Mr. Cantwell to produce a tightly symmetrical animated shot that appeared in the “Dawn of Man” sequence early in the film: a low-angle view of the mysterious black monolith on Earth, with clouds beyond it, the sun rising and a crescent moon above.
For “Close Encounters of the Third Kind” (1977), Mr. Cantwell contributed technical dialogue and created early computer-generated imagery of unidentified flying objects strafing the landing site at Devils Tower in Wyoming, for a sequence late in the film. His U.F.O. imagery did not make it into the film — Steven Spielberg, the director, relied instead on old-fashioned special effects technology created by Mr. Trumbull — but the subject of U.F.O.s intrigued Mr. Cantwell, who claimed to have once been part of a group that witnessed a mysterious object in the night sky.
In a provenance letter for an auction of his artifacts and memorabilia in 2014, he described the experience: “A silent intense light rose in the east, climbing to our zenith where, instantly doubling in brightness, it launched straight upward.”