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

2025-12-03

AI Summary

Existing Gaussian splatting-based rendering methods rely on proxy geometry for ray tracing, resulting in complex intermediate mesh construction, expensive ray-triangle intersection computations, and difficulty unifying differentiable ray tracing and rasterization. This paper introduces the first rendering pipeline that adopts triangles as unified, differentiable primitives—eliminating proxy geometry entirely and enabling direct differentiable ray tracing and rasterization over optimized Triangle Splatting representations. Our core innovation is elevating triangles to end-to-end trainable, general-purpose rendering primitives, thereby achieving deep integration of both rendering paradigms. The method maintains real-time performance while significantly improving novel-view synthesis quality—outperforming state-of-the-art Gaussian-based ray tracing approaches—and enables immediate rasterized rendering of optimized results.

Technology Category

• Computer Vision: Diffusion Models for Vision
• Search and Optimization: Sampling/Simulation-based Search
• Planning, Routing, and Scheduling: Replanning and Plan Repair

Application Category

• Security and Privacy: Data transparency and provenance
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Responsible Web: Data and user privacy-enhancing technologies for the Web

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.

Problem

• Unifying triangle primitives for differentiable ray tracing and rasterization
• Eliminating proxy geometry and costly intersection tests in rendering
• Achieving high-quality real-time rendering for particle-based 3D scenes

Innovation

• Triangle-based differentiable ray tracing pipeline
• Direct triangle rendering without proxy geometry
• Unifies primitives for ray tracing and rasterization