Runway is launching Act-One motion capture system that uses video and voice recordings to map human facial expressions onto characters using the company’s latest model, Gen-3 Alpha. Runway calls it “a significant step forward in using generative models for expressive live action and animated content.” Compared to past facial capture techniques — which typically require complex rigging — Act-One is driven directly and only by the performance of an actor, requiring “no extra equipment,” making it more likely to capture and preserve an authentic, nuanced performance, according to the company.

“The goal is to transpose an actor’s performance into a 3D model suitable for an animation pipeline,” Runway notes in a research post about the new tool, which it is rolling out gradually and expects to soon be universally available. (The screenshot below is from a sample video on the post.)

VentureBeat explains that “depicting realistic facial expressions in AI generated characters” has been a limitation for AI video creators, with most appearing “limited and difficult to control. But no longer.”

Runway — the New York-based startup whose investors include Nvidia, Google and Salesforce — “allows users to record video of themselves or actors from any video camera — even the one on a smartphone — and then transfers the subject’s facial expressions to that of an AI generated character with uncanny accuracy,” VentureBeat writes.

AI video creators are welcoming the tool, with VentureBeat quoting one appreciative fan calling it “a game changer.”

Runway launched its latest foundation model, Gen-3 Alpha, this summer, building it as a text-, image- and video-to-video generator.

“Although Runway’s Gen-3 Alpha model can create some impressive videos, one area where it has always been a bit weak is facial animation — particularly in creating accurate facial expressions on characters that can match the mood of the scene,” SiliconANGLE reports, adding that “in the filmmaking industry, facial animation is an intricate and expensive task.”

Runway is aiming to improve the process by updating its flagship model.