Octree-GS: Towards Consistent Real-time Rendering with LOD-Structured 3D Gaussians.

The recently proposed 3D Gaussian Splatting (3D-GS) demonstrates superior rendering fidelity and efficiency compared to NeRF-based scene representations. However, it struggles in large-scale scenes due to the high number of Gaussian primitives, particularly in zoomed-out views, where all primitives are rendered regardless of their projected size. This often results in inefficient use of model capacity and difficulty capturing details at varying scales. To address this, we introduce Octree-GS, a Level-of-Detail (LOD) structured approach that dynamically selects appropriate levels from a set of multi-scale Gaussian primitives, ensuring consistent rendering performance. To adapt the design of LOD, we employ an innovative grow-and-prune strategy for densification and also propose a progressive training strategy to arrange Gaussians into appropriate LOD levels. Additionally, our LOD strategy generalizes to other Gaussian-based methods, such as 2D-GS and Scaffold-GS, reducing the number of primitives needed for rendering while maintaining scene reconstruction accuracy. Experiments on diverse datasets demonstrate that our method achieves real-time speeds, being up to 10× faster than state-of-the-art methods in large-scale scenes, without compromising visual quality. Project page: https://city-super.github.io/octree-gs/.