UTrice: Unifying Primitives in Differentiable Ray Tracing and Rasterization via Triangles for Particle-Based 3D Scenes

TL;DR

This paper introduces a differentiable triangle-based ray tracing pipeline that directly uses triangles as primitives, achieving higher quality and real-time performance in rendering particle-based 3D scenes, and unifies ray tracing with rasterization methods.

Contribution

It presents a novel triangle-based ray tracing method that eliminates proxy geometry, unifies rendering primitives, and improves quality and efficiency in particle-based scene rendering.

Findings

Achieves higher rendering quality than existing methods.

Maintains real-time rendering performance.

Unifies ray tracing and rasterization primitives.

Abstract

Ray tracing 3D Gaussian particles enables realistic effects such as depth of field, refractions, and flexible camera modeling for novel-view synthesis. However, existing methods trace Gaussians through proxy geometry, which requires constructing complex intermediate meshes and performing costly intersection tests. This limitation arises because Gaussian-based particles are not well suited as unified primitives for both ray tracing and rasterization. In this work, we propose a differentiable triangle-based ray tracing pipeline that directly treats triangles as rendering primitives without relying on any proxy geometry. Our results show that the proposed method achieves significantly higher rendering quality than existing ray tracing approaches while maintaining real-time rendering performance. Moreover, our pipeline can directly render triangles optimized by the rasterization-based method Triangle Splatting, thus unifying the primitives used in novel-view synthesis.