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Class: TriRep

(Not recommended) Return simplices attached to specified vertices


SI = vertexAttachments(TR, VI)


SI = vertexAttachments(TR, VI) returns the vertex-to-simplex information for the specified vertices VI. For 2-D triangulations in MATLAB®, the triangles SI are arranged in counter-clockwise order around the attached vertex VI.

Input Arguments

TRTriangulation representation
VIVI is a column vector of indices into the array of points representing the vertex coordinates, TR.X. The simplices associated with vertex i are the i'th entry in the cell array. If VI is not specified the vertex-simplex information for the entire triangulation is returned.

Output Arguments

SICell array of indices of the simplices attached to a vertex. A cell array is used to store the information because the number of simplices associated with each vertex can vary. The simplices associated with vertex i are in the i'th entry in the cell array SI.


A simplex is a triangle/tetrahedron or higher dimensional equivalent.


Example 1

Load a 2-D triangulation and use TriRep to compute the vertex-to-triangle relations.

load trimesh2d
trep = TriRep(tri, x, y);
Find the indices of the tetrahedra attached to the first vertex:
Tv = vertexAttachments(trep, 1)

Example 2

Perform a direct query of a 2-D triangulation created using DelaunayTri.

x = rand(20,1);
y = rand(20,1);
dt = DelaunayTri(x,y);
Find the triangles attached to vertex 5:
t = vertexAttachments(dt,5);
Plot the triangulation:
hold on;
Plot the triangles attached to vertex 5 (in red):
hold off;

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