Particle-based representations of radiance fields such as 3D Gaussian Splatting have found great success for reconstructing and re-rendering of complex scenes. Most existing methods render particles via rasterization, projecting them to screen space tiles for processing in a sorted order. This work instead considers ray tracing the particles, building a bounding volume hierarchy and casting a ray for each pixel using high-performance GPU ray tracing hardware. To efficiently handle large numbers of semi-transparent particles, we describe a specialized rendering algorithm which encapsulates particles with bounding meshes to leverage fast ray-triangle intersections, and shades batches of intersections in depth-order. The benefits of ray tracing are well-known in computer graphics: processing incoherent rays for secondary lighting effects such as shadows and reflections, rendering from highly-distorted cameras common in robotics, stochastically sampling rays, and more. With our renderer, this flexibility comes at little cost compared to rasterization. Experiments demonstrate the speed and accuracy of our approach, as well as several applications in computer graphics and vision. We further propose related improvements to the basic Gaussian representation, including a simple use of generalized kernel functions which significantly reduces particle hit counts.
我们介绍了一种基于射线追踪的粒子辐射场渲染方法，以及对高斯表示的改进。以下是翻译： 辐射场的基于粒子的表示方法（如 3D 高斯散射）在复杂场景的重建和重新渲染方面取得了巨大成功。大多数现有方法通过光栅化来渲染粒子，将它们投影到屏幕空间的瓦片上，以排序的方式进行处理。本工作考虑对粒子进行射线追踪，构建边界体积层次结构，并使用高性能 GPU 射线追踪硬件为每个像素投射射线。 为了高效处理大量半透明粒子，我们描述了一种专门的渲染算法，该算法用边界网格封装粒子以利用快速的射线-三角形相交，并按深度顺序对批量交点进行着色。射线追踪的优势在计算机图形学中是众所周知的：处理非相干射线以产生次级光照效果（如阴影和反射），从机器人学中常见的高度扭曲的相机进行渲染，随机采样射线等。使用我们的渲染器，这种灵活性与光栅化相比几乎没有额外成本。 实验证明了我们方法的速度和准确性，以及在计算机图形学和视觉方面的多种应用。我们进一步提出了对基本高斯表示的相关改进，包括简单使用广义核函数，这显著减少了粒子命中次数。