What is it about?

Given an input 3D model, we address the problem of generating a closed, watertight surface triangle mesh that strictly encloses the input. The proposed algorithm is controlled via two user defined parameters: alpha and offset. Alpha controls the size of cavities that cannot be traversed during wrapping while offset controls the distance between the vertices of the output mesh and the input.

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Why is it important?

The enclosing property of the output wrap is mandatory for applications related to conservative distance queries, collision avoidance, or motion planning. Compared to other mesh-based approaches, our approach is reliable, simple and resilient to input defects. It performs well in terms of approximation and mesh quality. We demonstrate its industry-grade robustness on large-scale datasets, for a wide range of defects. Our C++ implementation is already matured into a generic component for the open source CGAL project.


The proposed approach bridges the gap between shrink-wrapping, alpha shapes and Delaunay refinement.

Pierre Alliez

Read the Original

This page is a summary of: Alpha wrapping with an offset, ACM Transactions on Graphics, July 2022, ACM (Association for Computing Machinery),
DOI: 10.1145/3528223.3530152.
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