Retargeting is a Performance Capture term in filmmaking. In virtual production, the nuances of this term take on special meaning. Here, we break down the definition to give you a starting point.
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Retargeting in virtual production is a technique used to apply performance capture data to a computer-generated character's skeleton. It’s an incredibly valuable tool, allowing us to take motion captured from humans and use it for larger characters such as CG dinosaurs or giant robots. Retargeting allows the animation of these characters to be less time-consuming and more accurate than manual animating.
A retargeter or technical director (TD) would be in charge of creating mappings between two different skeletons, one from the actor and another from the CG creature. They ensure that all of the motion captured from the actor matches up properly with the new CG character, making sure that their movements look natural.
Software like Autodesk Motion Builder and Maya are popular choices for retargeting in virtual productions. Each software has its own set of features and benefits; however, both programs allow users to quickly create mapping rules and adjust those if needed. Additionally, some software packages can even simulate skinning for realistic cloth simulation when re-targeting a character’s rig.
Regarding best practices for retargeting in virtual productions, it’s essential first to understand the nuances of the source footage. Understanding how the original performer moved will make it easier to transfer this movement onto a CG model accurately. Additionally, you should always strive to keep your retargeted animations as close as possible to the original source. Finally, because this is a highly technical process, it’s important to have an experienced TD on board who knows how to solve any problems which may arise during the retargeting process.