On the basis of his work on the low-budget quasi-student film "Dark Star," future "Alien" writer Dan O'Bannon was hired to create the special effects, after Jodorowksy failed to detect any sympathetic vibes in a meeting with the industry's reigning FX master at the time, Douglas Trumbull ("2001: A Space Odyssey"), whom the filmmaker dismisses as more a "technician" than a fellow truth-seeker.
After a meeting with “2001: A Space Odyssey” effects king Douglas Trumbull that did not go well (he was a technician, not an artist, Jodorowsky recalls) he seeks refuge in a Hollywood movie theater showing John Carpenter’s “Dark Star.”
He relates how he wanted 2001: A Space Odyssey wizard Douglas Trumbull to create his film's effects, changing his mind once he decided that Trumbull was a technician and not an artist; instead, he tapped Dark Star's Dan O'Bannon.
He rejected Douglas Trumbull of “2001” fame as his special effects coordinator because the man’s distant, mechanical attitude would make him impossible to work with, and opted for the more amenable Dan O’Bannon (of John Carpenter’s “Dark Star”) instead.
So he turned to Dan O'Bannon, who had worked on the inventive, low-budget SF movie Dark Star.