Quadrilateral Mesh Singularity Reduction via Minimum Templates

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Solution Overview

Problem

Current methods for generating quadrilateral meshes struggle to achieve both high geometric and topological quality, leading to numerical instability and other issues in applications like computational fluid dynamics and graphics, due to the presence of singularities, which are difficult to control and optimize.

Innovation Solution

The method involves replacing sub-meshes with Minimum Singularity Templates (MSTs) using a process that identifies and ranks singularities, applies a shortest path algorithm, and performs a breadth-first search to determine patches, which are then replaced with optimized templates to reduce singularities while maintaining geometric quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If automatic mesh generators are used to produce high geometric quality mesh, then geometric quality is improved, but topological quality deteriorates due to low optimization with respect to singularities

Engineering Contradiction:
Improvegeometric qualityVSAvoidtopological quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The mesh is divided into patches, and singularities are identified and treated locally within each patch. The algorithm segments the mesh into regions with singularities and regions without, allowing targeted optimization of topological quality in singularity-prone areas while preserving geometric quality achieved by automatic mesh generators.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the parameter of singularity count in patches by applying operations that reduce singularities. By systematically reducing the number of singularities in each patch while maintaining geometric constraints, the method improves topological quality without sacrificing the geometric precision produced by automatic generators.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If mesh improvement and refinement techniques are applied, then geometric quality is maintained, but control over topological quality remains very limited

Engineering Contradiction:
Improvegeometric qualityVSAvoidcontrol over topological quality
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The algorithm provides feedback control over topological quality by counting singularities in each patch and applying reduction operations when singularity counts exceed thresholds. This systematic feedback mechanism gives precise control over topological quality while preserving the geometric quality improvements from mesh refinement techniques.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The mesh optimization process performs self-service by automatically identifying patches with excessive singularities and applying reduction operations without external intervention. This self-service capability provides direct control over topological quality while maintaining the geometric quality achieved through refinement.

Inventive Principle:
Principle #25Self-service

3Reliability

If global optimization problems are formulated for quad and hex meshing, then both geometric and topological quality can be addressed, but computational expense increases and parametric tweaking becomes non-intuitive

Engineering Contradiction:
Improvetopological qualityVSAvoidcomputational expense
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The global optimization problem is segmented into local patch-level operations. Instead of optimizing the entire mesh globally, the algorithm processes individual patches independently, identifying and reducing singularities in each patch. This segmentation dramatically reduces computational expense while maintaining control over topological quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies local quality optimization by treating each patch independently with its own singularity count and reduction operations. This local approach allows intuitive control over topological quality in each region without the computational burden of global optimization, while still achieving overall mesh improvement.

Inventive Principle:
Principle #3Local quality

4Productivity

If local operations are applied to refine or coarsen quad mesh, then efficiency is improved, but additional singularities are created

Engineering Contradiction:
Improvemesh refinement efficiencyVSAvoidsingularity control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention converts the harmful effect of local operations creating singularities into a beneficial process by systematically identifying and reducing those singularities. Local refinement operations are permitted to提高效率, and then singularity reduction operations are applied to eliminate the harmful side effect, turning the creation of singularities into an opportunity for targeted topological optimization.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11017597B2Singularity reduction in quadrilateral meshes
Publication Date: 2021.05.25 WISCONSIN ALUMNI RES FOUND
  • US11017597B2 patent drawing
  • US11017597B2 patent drawing
  • US11017597B2 patent drawing

AI summary

Systems and methods for modifying and generating quadrilateral meshes for computer graphic structures include obtaining a polygon mesh representing a computer graphic structure, the polygon mesh comprising a plurality of polygonal faces and a plurality of singularities, determining, based on a first singularity of the plurality of vertices, selecting, based on one or more characteristics of the patch, a first minimum singularity template (MST) of a plurality of MSTs each representing a corresponding quadmesh that has three or fewer singularities, and replacing, within the polygon mesh, the patch with the first MST.