Augmented Sphere Tracing for Real-time Editing Mega-scale Periodic Shell-lattice Structures

Abstract

We propose an augmented sphere tracing (AST) pipeline that seamlessly integrates editing, rendering, and slicing of mega-scale periodic shell-lattice structures. Traditional STL-based pipelines face challenges such as time-consuming format conversions, high storage requirements, and complex blending issues between discrete lattice and shell components, often resulting in a loss of geometric accuracy. Alternatively, implicit-based pipelines excel at smooth modeling and robust Boolean operations but require inefficient and error-prone conversions of STL shells into implicit forms, complicating the rendering process. To address these issues, AST combines hybrid implicit lattice and mesh shell representations, eliminating the need for explicit 3D model construction and unnecessary geometric format conversions. It overcomes the major challenges of hybrid forms and mega-scale rendering by using an augmented tracing distance query that avoids costly signed distance field (SDF) calculations while preserving geometric details. Additionally, it employs a local tracing distance query within a single cell, leveraging lattice periodicity for efficiency. The pipeline also supports various types of shell-lattices in industrial applications, including blending, warping, field-directed distributions, region-specific cell types, and produces arbitrary directional slicing for manufacturing. As demonstrated by various examples implemented in WebGPU, AST archives high efficiency and accuracy in real-time rendering of shell-lattices with billions of beams on an RTX 3090, outperforming traditional pipelines in storage, frame time, and detail preservation.