HybridSim: A Physics-Learning Hybrid Digital Twin for mmWave Human Sensing

ECCV 2026

Synthesizing realistic mmWave radar signals from dynamic human meshes and fixed-room indoor scenes.

Weitao Xiong1,2   Tianyu Liu2   Peng Li2   Kok Chung Chua1
Toa Chean Khim1   Pu Wang3   Hongfei Xue3†

1Xiamen University   2The Hong Kong University of Science and Technology   3University of North Carolina at Charlotte
Corresponding Author

HybridSim teaser

Abstract

High-fidelity simulation of mmWave radar signals for dynamic human motion is valuable for developing radar-based human sensing models, but collecting accurately labeled measurements for each deployment site remains expensive.

HybridSim synthesizes mmWave radar signals from dynamic human meshes under a fixed indoor room configuration by decoupling propagation into direct inverse-rendering paths and indirect 3DGS-based paths. This hybrid design improves agreement with physically based references while keeping site-specific data augmentation practical.

Method Overview

Direct Radar Path

The primary reflection path is modeled with inverse rendering and a microfacet BRDF over the moving human surface.

Indirect Multipath

3D Gaussian Splatting and virtual receiver geometry approximate room-specific multipath interference efficiently.