Adaptive Refinement for Unstructured T-Splines with Linear Complexity

Research output: Contribution to journalArticleResearchpeer review

Authors

  • Roland Maier
  • Philipp Morgenstern
  • Thomas Takacs

Research Organisations

External Research Organisations

  • Friedrich Schiller University Jena
  • Johann Radon Institute for Computational and Applied Mathematics (RICAM)
  • Johannes Kepler University of Linz (JKU)
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Details

Translated title of the contributionAdaptive Verfeinerung für unstrukturierte T-Splines mit linearer Komplexität
Original languageEnglish
Article number102117
JournalCAD Computer Aided Design
Volume96
Early online date3 Jun 2022
Publication statusPublished - Jun 2022

Abstract

We present an adaptive refinement algorithm for T-splines on unstructured 2D meshes. While for structured 2D meshes, one can refine elements alternatingly in horizontal and vertical direction, such an approach cannot be generalized directly to unstructured meshes, where no two unique global mesh directions can be assigned. To resolve this issue, we introduce the concept of direction indices, i.e., integers associated to each edge, which are inspired by theory on higher-dimensional structured T-splines. Together with refinement levels of edges, these indices essentially drive the refinement scheme. We combine these ideas with an edge subdivision routine that allows for I-nodes, yielding a very flexible refinement scheme that nicely distributes the T-nodes, preserving global linear independence, analysis-suitability (local linear independence) except in the vicinity of extraordinary nodes, sparsity of the system matrix, and shape regularity of the mesh elements. Further, we show that the refinement procedure has linear complexity in the sense of guaranteed upper bounds on a) the distance between marked and additionally refined elements, and on b) the ratio of the numbers of generated and marked mesh elements.

Keywords

    Adaptive refinement, T-splines, Unstructured meshes

ASJC Scopus subject areas

Cite this

Adaptive Refinement for Unstructured T-Splines with Linear Complexity. / Maier, Roland; Morgenstern, Philipp; Takacs, Thomas.
In: CAD Computer Aided Design, Vol. 96, 102117, 06.2022.

Research output: Contribution to journalArticleResearchpeer review

Maier R, Morgenstern P, Takacs T. Adaptive Refinement for Unstructured T-Splines with Linear Complexity. CAD Computer Aided Design. 2022 Jun;96:102117. Epub 2022 Jun 3. doi: 10.48550/arXiv.2109.00448, 10.1016/j.cagd.2022.102117
Maier, Roland ; Morgenstern, Philipp ; Takacs, Thomas. / Adaptive Refinement for Unstructured T-Splines with Linear Complexity. In: CAD Computer Aided Design. 2022 ; Vol. 96.
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abstract = "We present an adaptive refinement algorithm for T-splines on unstructured 2D meshes. While for structured 2D meshes, one can refine elements alternatingly in horizontal and vertical direction, such an approach cannot be generalized directly to unstructured meshes, where no two unique global mesh directions can be assigned. To resolve this issue, we introduce the concept of direction indices, i.e., integers associated to each edge, which are inspired by theory on higher-dimensional structured T-splines. Together with refinement levels of edges, these indices essentially drive the refinement scheme. We combine these ideas with an edge subdivision routine that allows for I-nodes, yielding a very flexible refinement scheme that nicely distributes the T-nodes, preserving global linear independence, analysis-suitability (local linear independence) except in the vicinity of extraordinary nodes, sparsity of the system matrix, and shape regularity of the mesh elements. Further, we show that the refinement procedure has linear complexity in the sense of guaranteed upper bounds on a) the distance between marked and additionally refined elements, and on b) the ratio of the numbers of generated and marked mesh elements.",
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