As a project moves into production, the technical advantages of previs begin to take center stage. Real-world measurements are derived from the previs shots to help streamline the live-action setups. Similar shots can be grouped together to save time, and the need for specialty equipment, such as camera cranes, can be identified in advance.
Basic camera statistics, such as focal length, camera height and tilt angle, are typically displayed in the mattebox below the previs imagery, so that they are available at all times. Leveraging this type of information on the day, is one of the great advantages of having worked out the staging in advance.
Ultimately, the previs team has to insure that their work is achievable in production. This is a huge responsibility given the equally important demand to keep previs quick and flexible. Previs teams have to be well versed in film language and on-set terminology to be qualified to advise the live-action crew. If a previs artist knows how their shots are likely to be accomplished, they can create relevant diagrams that will make sense to traditional filmmakers. Sometimes animated diagrams are requested to allow the filmmakers to review the previs choreography from an alternate point of view.
However, no amount of preparation can replace the need for some on-set previs support. Filmmaking is a spontaneous artform which is full of unexpected challenges. On-set previs can help solve problems on the fly and one step ahead of the camera crew. Often on-set previs artists will work with the visual effects supervisor to answer questions and mock up solutions based on the situation at hand. This is especially difficult if the production plans on using motion control camera rigs to playback the previs moves. Just a handful of previs supervisors are truly capable of supporting motion control crane operators, but if done correctly, the results can be identical to what the director signed off on in the previs.