Gaussian Blending

Rethinking Alpha Blending in 3D Gaussian Splatting

AAAI 2026

Seoul National University

Abstract

The recent introduction of 3D Gaussian Splatting (3DGS) has significantly advanced novel view synthesis. Several studies have further improved the rendering quality of 3DGS, yet they still exhibit noticeable visual discrepancies when synthesizing views at sampling rates unseen during training. Specifically, they suffer from (i) erosion-induced blurring artifacts when zooming in and (ii) dilation-induced staircase artifacts when zooming out. We speculate that these artifacts arise from the fundamental limitation of the alpha blending adopted in 3DGS methods.

Instead of the conventional alpha blending that computes alpha and transmittance as scalar quantities over a pixel, we propose to replace it with our novel \textit{Gaussian Blending} that treats alpha and transmittance as spatially varying distributions. Thus, transmittances can be updated considering the spatial distribution of alpha values across the pixel area, allowing nearby background splats to contribute to the final rendering.

Our Gaussian Blending maintains real-time rendering speed and requires no additional memory cost, while being easily integrated as a drop-in replacement into existing 3DGS-based or other NVS frameworks. Extensive experiments demonstrate that Gaussian Blending effectively captures fine details at various sampling rates unseen during training, consistently outperforming existing novel view synthesis models across both unseen and seen sampling rates.

Zoom-out

Zoom-in

Drop-in Replacement

Our Gaussian Blending can be easily integrated as a drop-in replacement into existing 3DGS-based or other NVS frameworks. Below are video comparisons between the original scalar alpha blending and our Gaussian Blending as a drop-in replacement in two different 3DGS-based methods: 2DGS and Scaffold-GS. Observe that our method effectively prevents dilation artifacts when zooming out.

2DGS

Scaffold-GS

BibTeX


@inproceedings{koo2026gb,
    author = {Koo, Junseo and Jeong, Jinseo and Kim, Gunhee},
    title  = {{Gaussian Blending: Rethinking Alpha Blending in 3D Gaussian Splatting}},
    booktitle = {Proceedings of the AAAI conference on artificial intelligence},
    year = {2026},
}