Facial Auto Rigging from 4D Expressions via Skinning Decomposition

This paper proposes a framework that utilizes skinning decomposition to automatically generate facial rigging from 4D expressions. The framework inputs a predefined rigging template and an actor's 4D facial expressions, including a neutral expression, as well as a group of arbitrary expressions. The output includes not only the linear blend skinning weights and joint positions of the actor's head mesh but also other facial components such as teeth and eyes. Compared to traditional methods, this paper applies a soft constraint to optimize joint positions and imposes a fixed sparsity distribution constraint to improve weight distribution. To further enhance rigging efficiency, this paper leverages GPU expression-parallel and CPU vertex-parallel strategies for joint transformation and weight updates, respectively. The experiments show that the proposed method generates high-fidelity facial rigging that outperforms existing solutions in terms of computational speed, joint position correctness, weight distribution correctness, or computational cost.