Most people think that being in the movies is incredibly glamorous. Most people have no idea what they are thinking. They know about the stars, the directors, and the producers. They may be aware that there are people who run the cameras, put on make-up and make costumes. And of course, the FX people usually get their own "extra" on the DVD. But even those people are dwarfed by the amazing constellation of skills on a major motion picture set.
You take, for example, set builders. These people can take an isolated piece of 4-lane road with a bridge and turn it into a major border crossing between two countries, complete with working electric gates, stoplights, booths equipped with cash registers, and clipboards that say "Dept. of Homeland Security" on them.
You have the prop guys. They obtain, make, and keep track of a thousand little things, from fake guns to badges to (in our case) hard hats. You have the electricians making sure the cameras have power, the lights are safely hooked up and the radios have batteries. The lighting people work with not just lights, but giant or small shades, reflectors, deflectors, and diffusers, to create the look the director needs.
There is a group of people who, when needed, can slap together platforms, or hook the cameras and lights to the most unlikely of objects in order to provide a stable place from which to film. There are drivers who bring in the equipment and ferry cast and crew back and forth from the set. You have the production assistants, those glorified gofers who become the most important people in an extra's world, who place you, tell you what to do and where to go, help handle props, bring coffee to the director, and a myriad other little tasks.
In the pre-dawn hours even Austin's awful traffic is pretty light, and despite initially turning the wrong way on Cesar Chavez Street, I managed to get to the gathering place (a city park pavilion) by 6:20AM. I was also very nearly whisked off to the set by a slightly over-zealous van driver before his partner managed to get someone on the radio to explain what I was supposed to do. And that was to go to the PA and sign in. This also included filling out your W2 tax form, something we had to do each and every day (said form has a littler mini-form on the back which asks for all of the same information you just wrote on its front -- I'm not kidding -- in addition to a series of boxes you check to indicate you are either a citizen, green card holder, or otherwise legally able to work in the United Sates. I'm not kidding about that, either). You need this to get paid, and extras don't rate having someone punch your data into a computer and getting it pre-printed.
After that, I grabbed a second breakfast (movie set food ranges from non-existent to amazing), walked over to Trailer City to get my overalls and a brief safety lecture from the power plant managers (lead paint, asbestos, explosive gases, don't mess with the controls, that sort of thing). Then we were off to the set.