It's a Foundry Nuke's plugin and a part KeenTools plugins suite. FaceTracker is in beta for Nuke 8 and above, running on Windows, Linux and macOS.
>> See Also: Simulating Physically Accurate Depth of Field in Nuke
Availability
FaceBuilder is currently available as a free download as part of the KeenTools product bundle, along with a 15-day trial of GeoTracker, KeenTools’ advanced 3D object tracker for Nuke.More Nuke Plugin [post_ad]