VLofcorruptedFL
by Tim C. Lueth, SG-Lib Toolbox: SolidGeometry 5.6 - EL/Edge Lists
Introduced first in SolidGeometry 4.1, Creation date: 2017-08-25, Last change: 2025-09-14
returns the vertex list indices of corrupted facets
Description
This function simply searches for vertex list indices such as [a a b], [a a a], i.e. corrupted facets that result from collapsing vertices when forced to a vertex grid.
See Also: VLmindxyz
, VLof2VLnonmanifold
Example Illustration
Syntax
[vi,fi,d,v1,v2,v3]=VLofcorruptedFL(FL)
Input Parameter
Output Parameter
vi: | | list of involved vertex points |
fi: | | list of corrupted facets |
d: | | index list [n x 3] describing which vertex of a list is doubled |
v1: | | vertices at position [1 2] |
v2: | | vertices at position [2 3 |
v3: | | vertices at position [3 1] |
Copyright 2017-2025 Tim C. Lueth. All rights reserved. The code is the property of Tim C. Lueth and may not be redistributed or modified without explicit written permission. This software may be used free of charge for academic research and teaching purposes only. Commercial use, redistribution, modification, or reverse engineering is strictly prohibited. Access to source code is restricted and granted only under specific agreements. For licensing inquiries or commercial use, please contact: Tim C. Lueth
Algorithm (Workflow)
This function, VLofcorruptedFL, identifies corrupted facets in a facet list (FL) where vertices are repeated, such as [a a b] or [a a a]. These corrupted facets often result from collapsing vertices when forced to a vertex grid.
Input Parameters
- FL: A matrix representing the facet list, where each row corresponds to a facet defined by three vertex indices.
Output Results
- vi: A list of unique vertex indices involved in corrupted facets.
- fi: A logical array indicating which facets in the list are corrupted.
- d: An index list [n x 3] indicating which vertices in each facet are duplicated.
- v1: Unique vertices where the first and second vertices of a facet are the same.
- v2: Unique vertices where the second and third vertices of a facet are the same.
- v3: Unique vertices where the third and first vertices of a facet are the same.
Algorithm Steps
- Compute logical arrays
d1, d2, and d3 to identify facets with repeated vertices:
d1: True if the first and second vertices of a facet are the same.d2: True if the second and third vertices of a facet are the same.d3: True if the third and first vertices of a facet are the same.
- Combine these logical arrays into a matrix
d with three columns, each representing one of the conditions above.
- Identify unique vertices involved in each type of duplication:
v1: Vertices where d1 is true.v2: Vertices where d2 is true.v3: Vertices where d3 is true.
- Combine
v1, v2, and v3 to form vi, the list of all unique vertices involved in corrupted facets.
- Determine which facets are corrupted by checking if any of the conditions in
d are true for each facet, resulting in the logical array fi.
Algorithm explaination created using ChatGPT on 2025-08-19 00:21. (Please note: No guarantee for the correctness of this explanation)
Last html export of this page out of FM database by TL: 2025-09-21