3D Gaussian Splatting (3DGS) has shown great potential for efficient reconstruction and high-fidelity real-time rendering of complex scenes on consumer hardware. However, due to its rasterization-based formulation, 3DGS is constrained to ideal pinhole cameras and lacks support for secondary lighting effects. Recent methods address these limitations by tracing volumetric particles instead, however, this comes at the cost of significantly slower rendering speeds. In this work, we propose 3D Gaussian Unscented Transform (3DGUT), replacing the EWA splatting formulation in 3DGS with the Unscented Transform that approximates the particles through sigma points, which can be projected exactly under any nonlinear projection function. This modification enables trivial support of distorted cameras with time dependent effects such as rolling shutter, while retaining the efficiency of rasterization. Additionally, we align our rendering formulation with that of tracing-based methods, enabling secondary ray tracing required to represent phenomena such as reflections and refraction within the same 3D representation.

翻译：3D Gaussian Splatting（3DGS）已在消费级硬件上展现出高效重建复杂场景并实现高保真实时渲染的巨大潜力。然而，由于其基于光栅化的构建方式，3DGS受限于理想针孔相机模型，且缺乏对二次光照效果的支持。近期研究通过追踪体素粒子来应对这些局限，但这导致了渲染速度显著下降。本研究提出3D Gaussian Unscented Transform（3DGUT），用Unscented Transform取代3DGS中的EWA splatting构建方式，该方法通过sigma点近似表示粒子，可在任意非线性投影函数下实现精确投影。这一改进使得系统能够轻松支持具有时变效应（如卷帘快门）的畸变相机，同时保持光栅化的高效性。此外，我们将渲染构建方式与基于光线追踪的方法对齐，从而实现在同一3D表征体系下进行反射、折射等现象所需的二次光线追踪。