RiGS: Rigid-aware 4D Gaussian Splatting from a Single Monocular Video

1Harvard University, 2Zhejiang University, 3Nanyang Technological University, 4University of Minnesota - Twin Cities

*Work done during a research internship at Harvard University. ^Corresponding author

Abstract

Reconstructing dynamic 3D scenes from monocular videos is a fundamental yet highly challenging task, as real-world motions often involve both long-term smooth transformations and short-term complex deformations. Existing methods either struggle to maintain temporal consistency or fail to capture high-frequency dynamics due to limited motion modeling capacity.

We present Rigid-aware 4D Gaussian Splatting (RiGS), which simultaneously captures motions across multiple temporal scales. RiGS introduces three types of Gaussian primitives: static, rigid, and transient, which represent static backgrounds, long-term low-frequency motions, and short-term high-frequency dynamics, respectively.

An object-wise dynamic mask aggregates long-range spatiotemporal motion information and guides the decomposition of static and dynamic regions. Rigid Gaussians can transition into transient Gaussians based on their temporal duration, and both are optimized under scene flow guidance, providing dense 3D motion supervision. Extensive experiments demonstrate state-of-the-art performance on novel view synthesis benchmarks.

Method

Pipeline of RiGS.
RiGS decomposes a monocular dynamic scene into static, rigid, and transient Gaussian primitives. Object-wise dynamic masks supervise static-dynamic decomposition, while scene flow guides dense 3D motion learning.

Static Gaussians

Represent background and temporally stable regions outside the dynamic mask.

Rigid Gaussians

Capture coherent long-term motion with low-frequency rigid transformations.

Transient Gaussians

Model fast, short-lived, high-frequency dynamics that rigid motion bases cannot express.

Object-wise dynamic mask overlay.
Object-wise dynamic masks aggregate long-range motion cues.
Rigid and transient Gaussian dot rendering.
Rigid Gaussians (blue) and transient Gaussians (red) separate long-term and short-term dynamics.

Results

RiGS improves novel view synthesis for scenes with large deformation, complex multi-object motion, and fast transient dynamics.

HyperNeRF result on Umbrella. MoSca result on Umbrella. RiGS result on Umbrella. Ground truth on Umbrella.
Umbrella
HyperNeRF MoSca RiGS Ground Truth
HyperNeRF result on Playground. MoSca result on Playground. RiGS result on Playground. Ground truth on Playground.
Playground
HyperNeRF MoSca RiGS Ground Truth
MoSca result on Judo. Shape of Motion result on Judo. RiGS result on Judo. Ground truth on Judo.
Judo
MoSca SoM RiGS Ground Truth
MoSca result on Dog Agility. Shape of Motion result on Dog Agility. RiGS result on Dog Agility. Ground truth on Dog Agility.
Dog Agility
MoSca SoM RiGS Ground Truth
Gaussian Marbles result on Block. MoSca result on Block. RiGS result on Block. Ground truth on Block.
Block
Marbles MoSca RiGS Ground Truth
Gaussian Marbles result on Paper Windmill. Shape of Motion result on Paper Windmill. RiGS result on Paper Windmill. Ground truth on Paper Windmill.
Paper Windmill
Marbles SoM RiGS Ground Truth

BibTeX

@misc{wu2026rigsrigidaware4dgaussian,
      title={RiGS: Rigid-aware 4D Gaussian Splatting from a Single Monocular Video}, 
      author={Chenyu Wu and Wanhua Li and Zhu-Tian Chen and Hanspeter Pfister},
      year={2026},
      eprint={2605.23672},
      archivePrefix={arXiv},
      primaryClass={cs.CV},
      url={https://arxiv.org/abs/2605.23672}, 
}