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.
三维高斯点云（3D Gaussian Splatting, 3DGS）在消费者级硬件上实现复杂场景的高效重建和高保真实时渲染方面展现了巨大潜力。然而，由于其基于光栅化的框架，3DGS 受限于理想针孔相机模型，且不支持次级光照效果。尽管近期方法通过跟踪体积粒子解决了这些局限性，但代价是渲染速度显著降低。 在本研究中，我们提出了 3D Gaussian Unscented Transform (3DGUT)，将 3DGS 中的 EWA 点云投影公式替换为无迹变换（Unscented Transform），通过使用 sigma 点来逼近粒子，并允许粒子在任意非线性投影函数下精确投影。此改进不仅保留了光栅化的效率，还能够轻松支持带有时间依赖效应（如滚动快门）的畸变相机。 此外，我们将渲染公式与基于追踪的方法对齐，从而在同一三维表示框架中支持次级光线追踪，以呈现诸如反射和折射等现象。3DGUT 通过结合光栅化的高效性与追踪方法的灵活性，为复杂场景的逼真渲染提供了一种创新的解决方案。