3D Gaussian Splatting has gained widespread adoption across diverse applications due to its exceptional rendering performance and visual quality. While most existing methods rely on rasterization to render Gaussians, recent research has started investigating ray tracing approaches to overcome the fundamental limitations inherent in rasterization. However, current Gaussian ray tracing methods suffer from inefficiencies such as bloated acceleration structures and redundant node traversals, which greatly degrade ray tracing performance. In this work, we present GRTX, a set of software and hardware optimizations that enable efficient ray tracing for 3D Gaussian-based rendering. First, we introduce a novel approach for constructing streamlined acceleration structures for Gaussian primitives. Our key insight is that anisotropic Gaussians can be treated as unit spheres through ray space transformations, which substantially reduces BVH size and traversal overhead. Second, we propose dedicated hardware support for traversal checkpointing within ray tracing units. This eliminates redundant node visits during multi-round tracing by resuming traversal from checkpointed nodes rather than restarting from the root node in each subsequent round. Our evaluation shows that GRTX significantly improves ray tracing performance compared to the baseline ray tracing method with a negligible hardware cost.

翻译：三维高斯泼溅技术因其卓越的渲染性能与视觉质量，已在众多应用中得到广泛采用。尽管现有方法大多依赖光栅化来渲染高斯元素，但近期研究开始探索光线追踪方法，以克服光栅化固有的根本性局限。然而，当前的高斯光线追踪方法存在效率低下的问题，例如臃肿的加速结构与冗余的节点遍历，这严重降低了光线追踪性能。本文提出GRTX——一套面向三维高斯渲染的软硬件协同优化方案，以实现高效的光线追踪。首先，我们提出一种为高斯基元构建精简加速结构的新方法。其核心思路在于：通过光线空间变换，各向异性高斯可被视作单位球体处理，从而显著减少BVH结构的规模与遍历开销。其次，我们在光线追踪单元中设计了专用的遍历检查点硬件支持机制。该机制通过从已保存的检查点节点恢复遍历，而非在每轮追踪中从根节点重新开始，消除了多轮追踪过程中的冗余节点访问。实验评估表明，与基线光线追踪方法相比，GRTX在可忽略的硬件成本下显著提升了光线追踪性能。