Feature-Preserving Offset Meshing

What is it about?

We introduce a new offset meshing method that handles clean 3D surface meshes of arbitrary geometry and topology—where “clean” refers to meshes that are watertight, manifold, and free of self-intersections. Our approach also extends to imperfect, or “dirty,” meshes that violate these conditions, although the problem becomes significantly more difficult in such scenarios, and faithful feature preservation near defective areas cannot always be assured. In contrast to prior techniques, which have largely focused on constant-radius offsets, our method is, to our knowledge, the first to support mitered offsets while effectively preserving sharp features. Our method is designed based on several core principles: 1) explicitly generating the offset vertices and triangles with feature-capturing energy and constraints; 2) prioritizing the generation of the offset geometry before establishing its connectivity, 3) employing exact algorithms in critical pipeline steps for robustness, balancing the use of floating-point computations for efficiency, 4) applying various conservative speed up strategies including early reject non-contributing computations to the final output. Our approach further uniquely supports variable offset distances on input surface elements, offering a wider range of practical applications compared to conventional methods. For benchmarking purposes, we performed an extensive comparison against state-of-the-art offset methods using a curated subset of the Thingi10K dataset. Our results demonstrate the superiority of our approach over current state-of-the-art methods in terms of element count, feature preservation, and non-uniform offset distances of the resulting offset mesh surfaces, marking a significant advancement in the field.

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Why is it important?

Offset mesh generation, which involves creating a parallel surface with a specific distance from a given shape, holds a place of critical importance in geometric modeling and mesh processing. This technique is fundamental in a variety of applications, including computer-aided design and engineering, real-time rendering and animation, robotics, and medical imaging. While robust solutions for constant-radius and mitered offsets have been thoroughly established for 2D curve offsetting, their extension to 3D geometries remains conspicuously limited. Existing methods for constant-radius offset typically suffer from critical issues that hinder their practical usage: lack of robustness in various geometric configurations, struggles to maintain the fidelity of the original shape especially for complex geometries with sharp edges and intricate details, and computational inefficiency when the offset distance is small. Moreover, current methodologies for 3D mesh offsetting fail to adequately replicate the sharp vertex features and controlled spike truncation characteristic of 2D mitered offsets, establishing a significant gap in current frameworks that this research addresses.