To achieve the best performance, we implement a fast variant of the relatively well known MTCNN face detection algorithm. To achieve this, we use a two stage architecture: face detection and FACS regression. The idea is for our deep learning-based method to take a video as input and output a set of FACS for each frame. An example of a FACS rig being exercised can be seen below. Despite being over 40 years old, FACS are still the de facto standard due to the FACS controls being intuitive and easily transferable between rigs. The one we use is called the Facial Action Coding System or FACS, which defines a set of controls (based on facial muscle placement) to deform the 3D face mesh. There are various options to control and animate a 3D face-rig. The framework described in this blog post was also presented as a talk at SIGGRAPH 2021. In this post, we will describe a deep learning framework for regressing facial animation controls from video that both addresses these challenges and opens us up to a number of future opportunities. This is particularly challenging at Roblox, where we support a dizzying array of user devices, real-world conditions, and wildly creative use cases from our developers.

Despite numerous research breakthroughs, there are limited commercial examples of real-time facial animation applications. However, animating virtual 3D character faces in real time is an enormous technical challenge. Facial expression is a critical step in Roblox’s march towards making the metaverse a part of people’s daily lives through natural and believable avatar interactions.

Roblox man face with hair