Immediate 3D Gaussian Splat Reconstruction of Unordered Input with Global Consistency

SIGGRAPH Conference Papers 2026

Andreas Meuleman 1,2,3      Linus Franke* 1,2      Boris Zhestiankin 1,2,4      Camille Montemagni 1,3      George Drettakis 1,2
1Inria      2Université Côte d'Azur      3Université de Rennes      4EPFL
1 2 3 4

Abstract

3D Gaussian Splatting (3DGS) has become the method of choice for reconstructing and real-time rendering of captured scenes. To capture a scene with good visual quality, continuous image sequences are usually combined with out-of-order shots for better scene coverage. Structure from motion can reconstruct such captures, but only after they are all available and often with high computational cost. Incremental reconstruction methods – often derived from SLAM solutions – provide immediate feedback, but cannot handle the out-of-order capture we require. We provide the first immediate feedback solution for such radiance field capture that provides global consistency. We first introduce a method for fast matching in out-of-order sequences, by repurposing visual place recognition models and a covisibility graph, and provide an efficient way to find highly connected keyframes, improving quality even for ordered sequences. We show how these steps – together with GPU optimization and careful Gaussian primitive placement – provide fast local reconstruction, in our challenging radiance field reconstruction case. We then introduce a novel cluster-based method, again using the covisibility graph, to provide efficient loop closure that does not require sequential input. Finally, to handle large scenes in our context, we introduce a progressive hierarchy that allows our method to scale to large environments, without compromising efficiency. Our results show we provide immediate feedback 3DGS reconstruction with good visual quality in several datasets, with up to thousands of input images.

Method overview: an unordered input image sequence is processed with pose estimation using place recognition and global consistency with loop closure, producing an immediate hierarchical Gaussian reconstruction.
Our method takes an unordered sequence of input RGB images and directly computes a radiance field from them. To achieve this, we introduce a fast online pose estimation approach building on fast visual place recognition, local bundle adjustment, loop detection and loop closure techniques. Furthermore, a hierarchical Gaussian model is jointly optimized, allowing immediate feedback of reconstruction results during arbitrarily large capture.
Our algorithm is the key technology used for the Inria GraphDeco spin-off OnTheFly .

BibTeX

@inproceedings{2026immediate3DGS,
  title={Immediate 3D Gaussian Splat Reconstruction of Unordered Input with Global Consistency},
  author={Meuleman, Andreas and Franke, Linus and Zhestiankin, Boris and Montemagni, Camille and Drettakis, George},
  booktitle={SIGGRAPH Conference Papers},
  year={2026}
}

Acknowledgments and Funding

This work was funded by the European Research Council (ERC) Advanced Grant NERPHYS, number 101141721 https://project.inria.fr/nerphys. Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the EU or the European Research Council. Neither the EU nor the granting authority can be held responsible for them. The authors thank Adobe and NVIDIA for donations. Experiments presented in this paper were carried out using the Grid'5000 testbed, supported by a scientific interest group hosted by Inria and including CNRS, RENATER and several Universities and other organizations (https://www.grid5000.fr). This work was granted access to the HPC resources of IDRIS under the allocation AD011015561R1 made by GENCI.