Perhaps one of the most iconic scenes in Star Wars: A New Hope is the trench run on the Death Star where Luke and his team of X-wing fighters fly low into a trench on the Death Star to avoid turret fire on their way to the Achilles heel of the massive space station: an exhaust port.
But this scene was not always the plan and was actually all thanks to a mistake in the Death Star's model. Colin Cantrell, former designer at Lucasfilms Industrial Lights and Magic VFX division explains more in a Reddit AMA.
He tells a story about how George Lucas saw the miniatures he had worked on and eventually invited him to work on a project that would later become Star Wars. Cantrell worked on the Death Star model as well as being the lead ship designer for the first film. He explains:
"I didn't originally plan for the Death Star to have a trench… When I was working with the mold, I noticed the two halves had shrunk at the point where they met across the middle. It would have taken a week of work just to fill and sand and refill this depression. So, to save me the labor, I went to George and suggested a trench. He liked the idea so much that it became one of the most iconic moments in the film!"
So next time you watch arguably the best scene in A New Hope, not only do you have Colin here to thank, but also the limitations of the time. Without the trench, this scene would probably be much less intense and interesting to look at. If the original trilogy was all CGI, the Death Star would probably be just a smooth, round ball instead of the pock-marked, textured, complicated murder machine it turned out to be.
