MATLAB: How to compute the resolution of a triangular mesh

median of lenght of edgesmesh resolutiontriangular 3d meshes

Hi,
I want to compute the resolution of a 3D triangular mesh, that is defined as the median of the length of all edges in this mesh. I have an .obj file that contains vertices and faces, and after extracting them in 2D arrays(vertex, face):
function tabMedian = ComputeMedian_jihad( vertex, face )
  %COMPUTEMEDIAN_JIHAD Summary of this function goes here
  %   Detailed explanation goes here
    tabMedian = zeros(1,34817);  
    j = 0;  
    for i = 1 : size(face,1)
        d1 = (vertex(face(i,1),1) - vertex(face(i,2),1)) * (vertex(face(i,1),1) - vertex(face(i,2),1)) + (vertex(face(i,1),2) - vertex(face(i,2),2))*(vertex(face(i,1),2) - vertex(face(i,2),2)) + (vertex(face(i,1),3) - vertex(face(i,2),3))*(vertex(face(i,1),3) - vertex(face(i,2),3));
        d1 = sqrt(d1);
        d2 = (vertex(face(i,2),1) - vertex(face(i,3),1))^2 + (vertex(face(i,2),2) - vertex(face(i,3),2))^2 + (vertex(face(i,2),3) - vertex(face(i,3),3))^2 ;
        d2 = sqrt(d2);
        d3 = (vertex(face(i,3),1) - vertex(face(i,1),1))^2 + (vertex(face(i,3),2) - vertex(face(i,1),2))^2 + (vertex(face(i,3),3) - vertex(face(i,1),3))^2 ;
        d3 = sqrt(d3);
        j = j + 1;
        tabMedian(j)   = d1;
        tabMedian(j+1) = d2;
        tabMedian(j+2) = d3;   
    end
so what i did is to compute the distance between each 2 vertices from the 3 ones that constain the face. then I stok them in an array.Then I use the matlab function median on the table returned by my function. But the problem here is that there will be a (number of vertices) redundancy.
So I would be grateful if you tell me if this is the good way to compute the resolution of the mesh, and how can I eliminate those redundancies.

Best Answer

If you have the nodal connectivity data matrix and coordinates in hand, use the following function: http://in.mathworks.com/matlabcentral/fileexchange/25555-mesh2d-automatic-mesh-generation/content/Mesh2d%20v24/connectivity.m
It gives you the length of all the edges. The code is very effective, fast and takes care of repetition of coordinates nodes.
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