HandSCS: Structural Coordinate Space for Animatable Hand Gaussian Splatting

Photorealistic and animatable hand avatars are essential forapplications such as AR/VR, gaming, and telepresence. Recent 3D Gaus-sian Splatting (3DGS) based avatar methods enable real-time renderingof articulated humans, but modeling hands remains challenging due totheir compact structure, frequent self-occlusions, and complex finger in-teractions. Existing approaches primarily rely on pose-driven transfor-mations while representing Gaussians in Euclidean space, lacking an ex-plicit structural association with the underlying skeleton, which makespreserving fine-grained hand structures under complex articulations diffi-cult. In this work, we introduce the Structural Coordinate Space (SCS),a skeleton-relative representation that assigns each Gaussian primitivean explicit structural coordinate with respect to the articulated handskeleton. SCS is constructed using a hybrid static–virtual bone basis to-gether with a distance–rotation structural descriptor that encodes thegeometric relationship between Gaussians and bones. Based on SCS, weenforce both intra-pose and cross-pose structural consistency by com-bining per-Gaussian residual embeddings for local appearance modelingwith structural correspondence across poses. Experiments demonstratethat our approach significantly improves structural consistency and pre-serves fine geometric details under challenging hand articulations com-pared with existing 3DGS-based avatar methods.