Enables local refinement at mesh markers
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I have marked the surfaces in the mesh that I want to refine and the tetrahedra where the faces are located (the row indexes and values have been extracted), but applying loop refinement refines the entire mesh, so how do I modify the program to enable refinement of parts of the mesh?
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1598341/image.png)
function [newVertices, newFaces] = linearSubdivision(vertices, faces)
% Linear subdivision for triangle meshes
global edgeVertex;
global newIndexOfVertices;
newFaces = [];
newVertices = vertices;
nVertices = size(vertices,2);
nFaces = size(faces,2);
edgeVertex= zeros(nVertices, nVertices);
newIndexOfVertices = nVertices;
% ------------------------------------------------------------------------ %
% create a matrix of edge-vertices and a new triangulation (newFaces).
%
% * edgeVertex(x,y): index of the new vertex between (x,y)
%
% 0riginal vertices: va, vb, vc.
% New vertices: vp, vq, vr.
%
% vb vb
% / \ / \
% / \ vp--vq
% / \ / \ / \
% va ----- vc -> va-- vr --vc
%
for i=1:nFaces
[vaIndex, vbIndex, vcIndex] = deal(faces(1,i), faces(2,i), faces(3,i));
vpIndex = addEdgeVertex(vaIndex, vbIndex);
vqIndex = addEdgeVertex(vbIndex, vcIndex);
vrIndex = addEdgeVertex(vaIndex, vcIndex);
fourFaces = [vaIndex,vpIndex,vrIndex; vpIndex,vbIndex,vqIndex; vrIndex,vqIndex,vcIndex; vrIndex,vpIndex,vqIndex]';
newFaces = [newFaces, fourFaces];
end;
% ------------------------------------------------------------------------ %
% positions of the new vertices
for v1=1:nVertices-1
for v2=v1:nVertices
vNIndex = edgeVertex(v1,v2);
if (vNIndex~=0)
newVertices(:,vNIndex) = 1/2*(vertices(:,v1)+vertices(:,v2));
end;
end;
end;
end
% ---------------------------------------------------------------------------- %
function vNIndex = addEdgeVertex(v1Index, v2Index)
global edgeVertex;
global newIndexOfVertices;
if (v1Index>v2Index) % setting: v1 <= v2
vTmp = v1Index;
v1Index = v2Index;
v2Index = vTmp;
end;
if (edgeVertex(v1Index, v2Index)==0) % new vertex
newIndexOfVertices = newIndexOfVertices+1;
edgeVertex(v1Index, v2Index) = newIndexOfVertices;
end;
vNIndex = edgeVertex(v1Index, v2Index);
return;
end
2 Comments
KSSV
on 24 Jan 2024
You have to input only those face which you want to refine. Might be you are inputting all the faces and vertices to the function.
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