After around 2 years of being a runner and constant networking, you may get the opportunity to be a 3rd assistant director. (This may happen sooner depending on your contacts and pure luck).
On a typical film set there is a 1st Assistant Director, one or more 2nd directors and more than likely more than one 3rd assistant director. While on the surface all of these jobs may appear similar, they all involve different tasks and require a different set of skills. The 3rd AD will normally be your first role after runner, this is because it is essential to have on set experience to be a 3rd AD. You can do this by either being a runner, or by applying for a film course that includes on set experience.
The 3rd directors main role is to assist the 2nd director, this will mainly involve ensuring that all extras are on the right set at the right time. 3rd director will also be involved in directing background action on set, as well as being a messenger between different apartments.
The skills that a 3rd AD needs are communication, organization, confidence and patience. While these qualities are important in all media careers, for a 3rd AD its especially important to posses. Communication is important as it will be your job to send messages across many different departments, often via radio, and without good communication skills this may lead to great confusion. You also need to communicate well with the other assistant directors, doing this well will ensure that the day runs smoothly. Other people a 3rd AD needs to communicate well to is the extras, this is to ensure that they all know where to be and when they need to be in or out of shot.
Organization is another quality that a 3rd AD needs, similar to the communication skill the 3rd AD will need to organize the extras to ensure that they are all at the right place at the right time. There could be hundreds of extras on a shoot day, and it is your job to organize them. Another part of staying organized is keeping in communication with your 1st and 2nd AD, knowing when and where you need to have your talent and get them there as efficiently as possible.
Confidence is key, if you portray confidence as a 3rd AD then not only will the talent who you are in charge of respect you more, but your bosses will see you as a more viable candidate for promotion. Id you are at any point unsure about your job or role in production then you will inspire no confidence in those around you. Patience is the final quality i have listed, this is important in the 3rd AD’s role as, things are happening all the time on set, and this can become stressful and distracting at times. A good 3rd AD needs to keep there cool and concentrate on his job at hand to ensure they can do it professionally and to a high quality.