DelaunayTri

I already have a triangulation (x,y,z,tri). How can I create a DelaunayTri class without re-triangulating?

Answer 1

[Divyam]

Hi @dk,

It is not possible to create a "DelaunayTri" object without re-triangulation. To create the "DelaunayTri " object you have to use the extracted points from the "triangulation" object. As of MATLAB R2024b, "DelaunayTri " class is not recommended and it's preferable to use the "delaunayTriangulation" class instead.

% Assume T is your Triangulation object 
T = triangulation([1, 2, 3; 1, 3, 4], [0, 0; 1, 0; 0, 1; 1, 1]);

% Extract the points
points = T.Points;

% Create a DelaunayTri object
delaunayTriObj = DelaunayTri(points);

% Define points to check
P = [0.5, 0.5; 0.75, 0.75; 0.25, 0.25];

% Use pointLocation to find the triangles containing the points
triangleIndices = pointLocation(delaunayTriObj, P);

% Display the results
fprintf('Triangle indices for the query points: [%s]\n', join(string(triangleIndices),','));

Triangle indices for the query points: [2,2,1]

For more information regarding the "delaunayTriangulation" class, refer to the following documentation: https://www.mathworks.com/help/matlab/ref/delaunaytriangulation.html

[Walter Roberson]

However, this series of steps involves re-triangulating, which the original poster hoped to avoid.

[Divyam]

I edited the answer and explicitly pointed out that it isn't possible to create a DelaunayTri object without re-triangulating the points.

Thanks for pointing it out Walter!

Answer 2

[Walter Roberson]

As of R2013a you can create a triangulation object, passing in the connectivity and x and y and z data.

Unfortunately, you cannot create a DelaunayTri object or delaunayTriangulation object without re-triangulating.