He created the look of the X-wing and the Death Star; he also worked on “2001: A Space Odyssey,” “Close Encounters of the Third Kind” and “WarGames.”Colin Cantwell, an animator, conceptual artist and computer expert who played significant production roles in seminal science fiction films like “2001: A Space Odyssey, “Star Wars” and “WarGames,” died on May 21 at his home in Colorado Springs, Colo. He was 90.His partner, Sierra Dall, said the cause was dementia.Mr. Cantwell’s work on several influential movies reached its peak with “Star Wars,” George Lucas’s hugely successful space opera. To impress Mr. Lucas, Mr. Cantwell built two elaborate steampunk-like spacecraft models from parts he had culled from dozens of hobbyist’s kits. He got the job before Mr. Lucas had found a studio.Mr. Cantwell produced the original designs for spacecraft familiar to fans of “Star Wars” (later retitled “Star Wars, Episode IV — A New Hope”): the X-wing, the Rebel Alliance’s starfighter; the TIE fighter, part of the Galactic Empire’s imperial fleet; the wedge-shaped Imperial Star Destroyer; the cockpit for the Millennium Falcon; and the Death Star, the Empire’s enormous battle station, with a weapon capable of destroying a planet.“Colin’s imagination and creativity were apparent from the get-go,” Mr. Lucas said in a tribute on a Lucasfilm “Star Wars” website, adding, “His artistry helped me build out the visual foundation for so many ships that are instantly recognizable today.”Describing the design of the X-wing, Mr. Cantwell said in an interview on Reddit in 2016: “It had to be ultracool and different from all the other associations with aircraft, etc. In other words, it had to be alien and fit in with the rest of the story.” He got the original concept, he said, from “a dart being thrown at a target in a British pub.”His original design of the Death Star did not include the meridian trench. But as he created the model, he realized that it would be easier to include it. And it turned out to be critical to the design: In the film, the trench contains a thermal exhaust port that proves to be the source of the Death Star’s destruction.Gene Kozicki, a visual effects historian and archivist, said that Mr. Cantwell was most likely the first person Mr. Lucas hired to design the spaceships.“George had some rough shapes in mind for the ships that would make you know these are the good guys and these are the bad guys, but the details were left to Colin to work out,” he said in a phone interview. “All his designs evolved; it was all a group effort, but Colin was the godfather of the models.”In an interview with the Original Prop Blog in 2014, Mr. Cantwell described his interplay with Mr. Lucas.“He would say, ‘Oh, I want an Imperial battle cruiser,’ and I’d say, ‘What scenes do you want to shoot with it and how big is it?’” Mr. Cantwell said. “He said, ‘Really big,’ and I’d say, ‘Is it bigger than Burbank?’”An X-wing starfighter, one of the spacecraft Mr. Cantwell designed for “Star Wars,” on display at the California Science Center in Los Angeles.Stephen Osman/Los Angeles Times via Getty ImagesColin James Cantwell was born on April 3, 1932, in San Francisco. His father, James, was a graphic artist, and his mother, Fanny (Hanula) Cantwell, was a riveter during World War II.As a child, Colin was fascinated by outer space but could not go anywhere for two years: After he was diagnosed with tuberculosis, his treatment involved being forced to sit immobilized in a dark room with a heavy vest across his chest to prevent coughing fits.“Suffice to say, nothing could slow me down after that!” he wrote on Reddit.He studied animation at the University of California, Los Angeles, where he received a bachelor’s degree in applied arts in 1957. A love of architecture led him to create building designs that he personally showed to Frank Lloyd Wright, who was impressed enough that Mr. Cantwell was invited to study at Wright’s school of architecture in Arizona. Mr. Cantwell was accepted, but when Wright died in 1959, he decided not to proceed.“Colin had no interest in working with any other architect,” Ms. Dall said in a phone interview, “so that ended his architectural career.”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.”Mr. Cantwell worked on two other movie projects after “Close Encounters” and “Star Wars”: “Buck Rogers in the 25th Century” (1979) and “WarGames” (1983). For “Buck Rogers,” he created a system that let animators simulate spacecraft movements as they designed space battles.“Colin’s imagination and creativity were apparent from the get-go,” George Lucas said of Mr. Cantwell.Sierra DallHe also worked as a computer consultant for Hewlett-Packard, where he helped develop the first color display systems for desktop computers. He and a team working on “WarGames” used the company’s computers to create the graphics — projected on giant screens at the North American Aerospace Defense Command facility — that appeared to show a massive nuclear attack by the Soviet Union against the United States.Mr. Cantwell also wrote two science fiction books, “CoreFires” (2016) and “CoreFires2” (2018), about what happens to humanity after it has colonized the galaxy.Ms. Dall is his only immediate survivor.A year after the release of “2001,” Mr. Cantwell played a role in the reality of space exploration. As a liaison between NASA and CBS News, he sat a few feet from the anchorman Walter Cronkite, feeding him information, during the moon landing of Apollo 11 on July 20, 1969.“Halfway through the final descent, I alerted Walter to my detection of an orbit change that would consume more fuel, but allow coasting a little further than the planned target,” Mr. Cantwell told Reddit. “When the other TV stations had the ship landed according to their NASA manual, I determined that the Apollo had not yet landed. This was later confirmed that I had the accurate version of landing.” More