Move a Point on a 3D surface
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Hello,
I have a 3D surface with the information on the vertices and faces in a matrix. I also have a point that is located on the surface. I would like to move this point in x direction on the surface. So that I can be sure that the new point is also on the surface.
Could someone please help me with that problem?
Thank you,
Theresa
采纳的回答
% Generate test mesh
x = 1:15; y = 1:15;
[X,Y] = meshgrid(x,y);
Z = peaks(15);
F = delaunay(X,Y);
% Your points to be projected, with moving xq constant yq
% NOTE: In your case just take the (xknown,yknown) to
% xq = xknown + 2; yq = yknown; to move them at distance 2
xq = linspace(min(x),max(x),101);
yq = 8+zeros(size(xq));
% Build some useful matrices and coordinates in arrays
xyz = [X(:) Y(:) Z(:)]';
xyzF = reshape(xyz(:,F'), 3, 3, []);
baryMat = xyzF;
baryMat(3,:,:) = 1;
figure
trisurf(F,X,Y,Z);
colormap gray
hold on
for k = 1:length(xq)
xyq = [xq(k); yq(k); 1];
w = pagemldivide(baryMat, xyq);
i = find(all(w >= 0, 1), 1); % which face contain the point
if isempty(i)
% point outside the mesh
continue
end
xyzq = xyzF(:,:,i) * w(:,:,i);
plot3(xyzq(1), xyzq(2), xyzq(3), 'g.', 'Markersize', 10)
end
3 个评论
Theresa Kandels
2023-8-11
Bruno Luong
2023-8-11
But earlier you wrote "I have a 3D surface with the information on the vertices and faces in a matrix."
So what do you have?
In my code Vertice is
xyz' % n x 3
and face is
F % m x 3
If you only have vertices you might be able to reconstruct connectivity with delaunay as I did.
Explain exactly what you have if you don't want me to guess and fail.
Theresa Kandels
2023-8-11
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