Unreal Engine developer Epic Games has released Live Link Face, an iPhone app that uses the front-facing 3D sensors in the phone to do live motion capture for facial animations in 3D projects like video games, animations, or films.

The app uses tools from Apple's ARKit framework and the iPhone's TrueDepth sensor array to stream live motion capture from an actor looking at the phone to 3D characters in Unreal Engine running on a nearby workstation.

To many, the iPhone's TrueDepth sensor array seemed like a solution in search of a problem—Touch ID worked just fine for most people's' purposes in earlier iPhones, and there weren't many clear applications of the technology besides Face ID.

The motion capture the iPhone's sensors can manage is not as accurate as what's used by triple-A game development studios or major motion pictures, of course, so those high-end studios won't be dropping their kitted-out mo-cap studios for iPhones right now.

For those not familiar, Unreal Engine began life as a graphics engine used by triple-A video game studios for titles like Gears of War and Mass Effect, and it has evolved over time to be used by indies and in other situations like filmmaking, architecture, and design.

It competes with another popular engine called Unity, as well as in-house tools developed by various studios.