Ralph McQuarrie: Artist and Oscar-winnner best known for his designs for 'Star Wars'

Ralph McQuarrie designed several futuristic films but is best-known for visualising the landscapes of Star Wars and designing characters including Chewbacca, R2-D2 andC-3PO. It led to more "space" projects but he also worked on other science-fiction and fantasy projects and won an Oscar for Cocoon.

McQuarrie was raised on a farm in Montana and the family later moved to Vancouver. After technical college he signed up, went to Korea and was wounded by a bullet to the head. Back home, he studied at the Art Center School, then based in Los Angeles. McQuarrie was fascinated by planes and space exploration. After working as a graphic designer, including illustrating dental equipment and teeth, he joined Boeing, as a technical illustrator also storyboarding short films, before creating animated sequences showing the Apollo space missions.

Some film poster designs led to work on Star Dancing, an unmade science-fiction film, and, in turn, to an introduction to George Lucas, He was planning a space fantasy and liked McQuarrie's painting of a robot conducting a séance using a machine that creates a three-dimensional holographic image, but he was finishing his film American Graffiti. A couple of years later Lucas returned with the script of Star Wars. He asked McQuarrie to create some designs untrammelled by practicality. McQuarrie let his imagination go in part because he didn't think the film would ever get made: "He had a concept for big spectacular visuals which didn't come across from the script, so I tried to give it scale, juxtaposing those little figures with the big spectacular backgrounds."

Lucas included them with the script, and it is probable that without thosevisual cues, strongly geometric but often with ambiguous perspectives, the studio would have rejected the idea. Lucas recalled: "when words could not convey my ideas, I could always point to one of Ralph's fabulous illustrations and say, 'Do it like this.'"

McQuarrie's illustration helped Anthony Daniels formulate his performance as C-3PO, and his contribution extended beyond the visual: he added breathing apparatus to Darth Vader's iconic Samurai-inspired black helmet, leading to his distinctive rasp.

With The Empire Strikes Back some way off, McQuarrie joined television's Battlestar Galactica, "a sort of Wagon Train in outer space", but withdrew when the parallels with Lucas's film became too close. Paramount also approached him to work with Ken Adam on what would have been the first Star Trek movie, but Planet of the Titans was abandoned, as was an idea to return to TV, though some of their concepts turn up in The Search for Spock and the Next Generation series.

Back on Star Wars, McQuarrie's had less input into The Empire Strikes Back (1980), though he did have a partially anagramaticised cameo as the rebel General Pharl McQuarrie. For the film's 30th anniversary the General was added to the action figures range.

There was even less original work for Return of the Jedi (1982) and McQuarrie chose to pass on the three prequels, though his work obviously inspired them, while some unused designs were used in the TV series Clone Wars. He also designed Chewbacca's home for the TV Star Wars Holiday Special (1978), a scene that the saga returns to in Revenge of the Sith (2005).

The major part of McQuarrie's film work came from Lucas's special effects company Industrial Light and Magic – he designed a sequence for The Golden Child (1986) - and Spielberg. Spielberg asked for designs of the motherships in Close Encounters of the Third Kind (1977) ("to look like an oil refinery") and ET the Extra-Terrestrial (1982) ("like Dr Seuss designed it") and requested some alternate ideas for ET himself, though Carlo Rambaldi's classic design was pretty much already chosen. For Raiders of the Lost Ark (1981) McQuarrie created the illustration in the book giving the first view of the Ark. Spielberg also paid wry homage byincluding R2-D2 and C-3PO among the hieroglyphs.

In 1985 McQuarrie won an Oscar for the luminous special effects of Cocoon about a group of pensioners being rejuvenated in a swimming pool in which aliens have temporarily stored some cocoons. Masters of the Universe (1987), a spin-off from the animated series, starred the similarly two-dimensional Dolph Lundgren, but the debt to Star Wars was clear as black-caped Vader-like figures stalked the landscape. For Clive Barker's Nightbreed (1990) McQuarrie created the huge mural; "a chronicle, a kind of catalogue of these creatures and the normals who are in the process of becoming the Breed."

Among McQuarrie's unmade work is the first version of Robocop, Irvin Kirshner's Forbidden Planet remake, and the TV series Cozmo's Bar and Grill – apparently something like Cheers set in the Star Wars cantina – while his idea for a microscopic city in the sci-fi series *batteries not included was rejected as too expensive.

Outside film, he helped design Universal Studio's Back to the Future theme park ride and the PortAventura theme park in Salou, Catalonia; he also designed many book covers, including some for books by Isaac Asimov.

Ralph Angus McQuarrie, artist and illustrator: born Gary, Indiana 13 June 1939; married 1983 Joan Benjamin; died Berkeley, California 3 March 2012.