With the rapid development of virtual reality and augmented reality technologies, the demand for personalized virtual avatars has become increasingly urgent. Recently, researchers proposed a new technology called URAvatar (Universal Relightable Gaussian Codec Avatar), which allows users to easily generate high-fidelity virtual avatars by scanning with their phones. This innovative achievement not only enhances the visual effects of virtual avatars but also enables users to drive and adjust their avatars in real-time under different lighting conditions. The working principle of URAvatar is based on a complex light transport model, and it differs from previous approaches.