Summary of 3GPP Change Request S4-260147

Document Information

• Source: Pengcheng Laboratory, China Mobile Com. Corporation
• Title: [FS_3DGS_MED] Pseudo-CR on Enhanced Scenario for Avatar Communication Use Case
• Specification: 3GPP Draft TR 26.958 v0.1.1
• Meeting: TSG-SA4 Meeting #135, 9-13 February 2026, Goa, India

Main Objective

This contribution proposes an enhanced scenario for avatar-based communication that combines parametric human models with 3D Gaussian Splatting (3DGS) technology. The proposal aims to enable efficient real-time interactive communication by transmitting compact motion parameters to drive a deformable mesh while using 3DGS for high-fidelity appearance rendering.

Technical Contributions

Enhanced Avatar Communication Architecture

The proposal introduces a hybrid representation approach consisting of:

• Deformable mesh representation driven by parametric human model parameters (e.g., SMPL-X for body/hands, FLAME for face)
• 3D Gaussian Splat representation for appearance enhancement and fine detail capture
• Separation of geometry and appearance to optimize transmission efficiency

Technical Processing Pipeline

Sender Side Processing

• Capture: User captured using one or more cameras
• Parameter Extraction: Geometric and animation parameters extracted using parametric models
• SMPL-X for body and hand motion
• FLAME for facial geometry and expression
• Representation Generation:
• Deformable human mesh reconstruction based on extracted parameters
• 3D Gaussian Splat generation for appearance details (fine surface detail, hair, clothing)
• Spatial Alignment: 3DGS representation aligned with deformable mesh

Transmission Strategy

• Base Avatar: Transmitted once at session setup or updated occasionally
• Rigged mesh with skeletal structure and blendshapes
• Static 3DGS representation
• Animation Stream: Time-varying model parameters transmitted during session
• Compact parametric representation
• Low-latency transmission for interactive communication
• Update Frequency: 3DGS updated at lower frequency than animation parameters

Receiver Side Processing

• Animation Application: Received parameters drive avatar motion
• Deformation Propagation: 3DGS follows mesh deformation
• Rendering: Composite approach combining:
• Mesh-based shading
• 3DGS-based appearance contributions
• Viewpoint Adaptation: Supported within application-defined constraints

Working Assumptions

The proposal defines several key working assumptions:

Capture and Animation Extraction:
- Real-time capture using one or more cameras
- Real-time derivation of animation parameters from captured signals

Representation:
- Deformable mesh with associated rig
- Associated 3DGS for appearance rendering
- Static or low-frequency updated 3DGS representation

Transmission:
- One-time or occasional base avatar transmission
- Continuous time-varying animation parameter transmission
- Low-latency requirement for interactive communication

Decoding and Rendering:
- Animation parameter application at receiver
- Combined mesh and 3DGS rendering
- Constrained viewpoint adaptation support

Key Innovation

The main technical innovation is the separation of geometric animation (transmitted as compact parametric data) from appearance representation (using 3DGS), enabling photorealistic real-time avatar communication with efficient bandwidth utilization suitable for bidirectional interactive applications.