# groupVertices

Below is a demonstration of the features of the groupVertices function

## Contents

```clear; close all; clc;
```

## Syntax

[groupIndexVertices,groupIndexFaces]=groupVertices(F,V,waitBarOption);

## Description

This function takes in a description of a tesselation, consisting of an array F (faces or elements), and V (vertices). The output is represents the group index for each point in groupIndexVertices and the group index of each face in groupIndexFaces. Vertices which are connected to the same mesh obtain the same group indes. Face indices are derived from the vertex indices.

## Example 1: Seperating patch data into groups

Creating test data consisting of seperates sets faces and vertices

```numGroups=3;
F_cell=cell(1,numGroups);
V_cell=cell(1,numGroups);
for q=1:1:numGroups
switch q
case 1
[F,V]=geoSphere(3,1);
case 2
[F,V]=stanford_bunny('g');
case 3
[F,V]=graphicsModels(3);
end
%     [F,V]=subtri(F,V,1);
V=V-mean(V,1);
V=V./max(V(:));
V(:,1)=V(:,1)+q*2;
F_cell{q}=F;
V_cell{q}=V;
end
[F,V]=joinElementSets(F_cell,V_cell);
```

Using groupVertices to split the vertices into groups

```[groupIndexVertices,groupIndexFaces]=groupVertices(F,V,1);
```

Visualizing the resulting grouping

```cFigure;
subplot(2,1,1); hold on;
title('Ungrouped')
gpatch(F,V,'kw','none');
axisGeom;
camlight headlight;

subplot(2,1,2); hold on;
title('Grouped')
gpatch(F,V,'kw','none');
scatterV(V,15,groupIndexVertices,'filled');
axisGeom;
camlight headlight;
colormap gjet; icolorbar;
drawnow;
```

If desired a second output can be requisted which represents the face groupings.

```cFigure;
title('Grouped faces')
gpatch(F,V,groupIndexFaces,'none');
axisGeom;
camlight headlight;
colormap gjet; icolorbar;
drawnow;
```

GIBBON www.gibboncode.org

Kevin Mattheus Moerman, gibbon.toolbox@gmail.com

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GIBBON: The Geometry and Image-based Bioengineering add-On. A toolbox for image segmentation, image-based modeling, meshing, and finite element analysis.

Copyright (C) 2019 Kevin Mattheus Moerman

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

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