A Voxel-based Rendering Pipeline for Large 3D Line Sets

TL;DR

This paper introduces a voxel-based GPU ray-casting pipeline for large 3D line sets, enabling scalable, transparent, and globally illuminated rendering that surpasses traditional rasterization in performance and visual effects.

Contribution

It proposes a novel direction-preserving encoding of lines into a voxel grid and a GPU ray-casting method for scalable, high-quality rendering of large 3D line datasets.

Findings

Superior rendering performance compared to rasterization.

Interactive rendering of transparent lines and global illumination effects.

Effective level-of-detail approach for illumination simulation.

Abstract

We present a voxel-based rendering pipeline for large 3D line sets that employs GPU ray-casting to achieve scalable rendering including transparency and global illumination effects that cannot be achieved with GPU rasterization. Even for opaque lines we demonstrate superior rendering performance compared to GPU rasterization of lines, and when transparency is used we can interactively render large amounts of lines that are infeasible to be rendered via rasterization. To achieve this, we propose a direction-preserving encoding of lines into a regular voxel grid, along with the quantization of directions using face-to-face connectivity in this grid. On the regular grid structure, parallel GPU ray-casting is used to determine visible fragments in correct visibility order. To enable interactive rendering of global illumination effects like low-frequency shadows and ambient occlusions, illumination simulation is performed during ray-casting on a level-of-detail (LoD) line representation that considers the number of lines and their lengths per voxel. In this way we can render effects which are very difficult to render via GPU rasterization. A detailed performance and quality evaluation compares our approach to rasterization-based rendering of lines.