3D Rendering Techniques for a Virtual Avatar System in Live Streaming

The background explains the need for advanced 3D rendering in live streaming to provide immersive, interactive experiences beyond traditional 2D graphics, leading to the development of a virtual avatar system with multiple functional modules.

Layered Rendering : Describes a multi‑instance, multi‑window architecture where different layers (e.g., 3D effects, avatars, gifts) are rendered independently, allowing flexible composition, independent lifecycles, and easy insertion of UI elements such as bullet comments.

Avatar Customization – Mesh Swapping and Accessories : Details how clothing changes replace mesh vertices while sharing the same skeleton, and how accessories act as child objects that inherit bone animation, supporting skinning, coloring, and bone manipulation.

Bone Manipulation (High‑Heel Replacement) : Explains using skeletal offsets to transform foot bones when swapping flat shoes for high heels, and similarly for chest deformation, with incremental matrix adjustments for runtime height changes.

HSV‑Based Coloring : Introduces HSV color space for dynamic skin, eye, clothing, and accessory recoloring, keeping saturation and value constant while adjusting hue, and outlines the RGB→HSV→Hue‑adjust→RGB conversion process.

Depth Handling : Discusses z‑buffer usage, z‑fighting issues, and mitigation strategies such as spacing objects, adjusting near‑plane distance, maintaining appropriate camera distance, and balancing buffer precision.

Transparent Object Rendering : Covers challenges of rendering hair and foliage, compares painter's algorithm, depth peeling, and alpha‑to‑coverage, and adopts a two‑pass approach (opaque first, transparent second without depth write) to avoid holes.

Shadow Techniques : Compares hard stencil‑volume shadows with soft shadow‑map based shadows, explains two‑pass shadow mapping, PCF filtering, and shows visual results for character accessories and clothing.

Physically‑Based Rendering (PBR) : Describes the shift from Phong/Blinn‑Phong to PBR, detailing direct and indirect lighting, HDR environment maps, and the core PBR components (normal distribution, Fresnel, geometry functions). It also lists required texture maps (albedo, roughness, metallic, normal, ambient occlusion, emissive) and shows final rendered examples.