Markers on actor's face

This is a technique for recording intricate changes in facial expressions. The markers used for this task are small enough to be attached even to an eyelid.

They are registered by six cameras operating in infrared light – a perfect solution for facial motion capture, the “Holy Grail” of it, because the infrared light is invisible to the eye (like that emitted by any infrared remote control) which spares the actors the inconvenience of  having light shine directly in their eyes.

It is possible to create a mixed setup; some of the cameras record full body motion capture and some are focused on smaller areas, where facial recording can take place. Generally, cameras operate like human eyes and so small facial markers could be recognized only within a close distance (~1.5 meters) to the camera; large full body markers work from as far as 9 meters, on the other hand.

The marker set must be designed and calibrated depending on the software and control rig setup to which the moves will be targeted, so it is advisable to test them before the actual shoot to solve potential problems early on.

Generally, depending on the purpose of the data, one may use Autodesk MotionBuilder, Softimage FaceRobot or various plug-ins for Max, Maya and other packages.

Another option is creating a custom face rig, however due to intricate motions, human faces are extremely hard to replicate accurately and so minor imperfections can become very visible and disrupt the final result.

The markers are relatively small, which makes it possible to key them out with little effort from a video footage simply by using a faint coloured light placed close to the camera lens. This way we can record MoCap data and real video footage of actor's face at the same time, so later we can blend the real video footage to CGI model.

It is possible to record audio for reference or even production simultaneously. Keep in mind that the stage is essentially a large, empty room and so excessive echoes may alter the actor's voice inevitably.