  We present SplattingAvatar, a hybrid 3D representation of photorealistic
human avatars with Gaussian Splatting embedded on a triangle mesh, which
renders over 300 FPS on a modern GPU and 30 FPS on a mobile device. We
disentangle the motion and appearance of a virtual human with explicit mesh
geometry and implicit appearance modeling with Gaussian Splatting. The
Gaussians are defined by barycentric coordinates and displacement on a triangle
mesh as Phong surfaces. We extend lifted optimization to simultaneously
optimize the parameters of the Gaussians while walking on the triangle mesh.
SplattingAvatar is a hybrid representation of virtual humans where the mesh
represents low-frequency motion and surface deformation, while the Gaussians
take over the high-frequency geometry and detailed appearance. Unlike existing
deformation methods that rely on an MLP-based linear blend skinning (LBS) field
for motion, we control the rotation and translation of the Gaussians directly
by mesh, which empowers its compatibility with various animation techniques,
e.g., skeletal animation, blend shapes, and mesh editing. Trainable from
monocular videos for both full-body and head avatars, SplattingAvatar shows
state-of-the-art rendering quality across multiple datasets.
