creating 3D mesh for some points in space

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lala
lala 2013-2-10
回答： Shivam Anand 2022-5-11
So I have these points, A, B, C, ... in 3D. Their coordinates are denoted by x, y, z. For example point A has these coordinates: if x=2.5 and y=12, then z is 3, and B is x=4, y=3, and z=15; and so on.
So i created three arrays to show my points:
x=[2.5 4 6 18 9]; y=[12 3 7.5 1 10]; z=[3 15 16 8 11.5];
and i want to create a 3D mesh from my points (A, B, ...). There are total of 9 points.
I am able to create plot3 and/or scatter3 but not mesh :(
Ive spent already a full week on this and read many tutorials and such but i just get more confused and dont get it. Please help! Thanks!
lala-
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Kaixiang Wang
Kaixiang Wang 2017-1-30
A mesh for only nine points? And z is not a function of x and y? What sort of visual result are you expecting?

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回答（9 个）

Patrick Kalita
Patrick Kalita 2013-2-13
trimesh is probably what you want to use. You can also use delaunay to generate the triangulation matrix that trimesh requires.
x=[2.5 4 6 18 9];
y=[12 3 7.5 1 10];
z=[3 15 16 8 11.5];
tri = delaunay(x, y);
trimesh(tri, x, y, z);
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lala
lala 2013-2-18
Thanks. This is good but i think a smoother sruface like like surface mesh is what im looking for. Something to show at x and y coordinates, what is the z (distance.) I have about 9 z distances and basically want to find a good visual way. But thanks again.
L-

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Parker Hinton
Parker Hinton 2017-5-26
Yes all, there is a solution, it has been stated. "Use griddata() or TriScatteredInterp to interpolate a grid of data from your points; then you can create a mesh from that."
Azzi Abdelmalek
Azzi Abdelmalek 2013-2-10
编辑：Azzi Abdelmalek 2013-2-10
You can't use mesh with your data. You will need more data. for example
x=[2.5 4 6 18 9];
y=[12 3 7.5 1 10];
[X,Y]=meshgrid(x,y)
% and for example
Z=X+Y
mesh(X,Y,Z)
% To understand, to create a mush plot with x=[1 2], and y=[ 10 20], you need
x=1,y=10
x=1,y=20,
x=2,y=10,
x=2,y=20
%to obtain these combinations we use
x=[1 2],
y=[ 10 20]
[X,Y]=meshgrid(x,y)
% find the corresponding z to each point
Z=cos(X+Y) % for example
mesh(X,Y,Z)
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lala
lala 2013-2-18
Thanks for explanation. But since my Z is not a function of X and Y, i guess mesh and meshgrid could not be useful.

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Walter Roberson
Walter Roberson 2013-2-11
Use griddata() or TriScatteredInterp to interpolate a grid of data from your points; then you can create a mesh from that.
Or you may wish to create a trimesh() once you have done a triangulation.
Benoit Botton
Benoit Botton 2014-12-4
Lala,
did you ever find a solution? I have the same issue
Bhuvan Varugu
Bhuvan Varugu 2015-4-14
I have the same issue. Please share some knowledge on this if you can?
fauer781
fauer781 2017-1-7
Hi, I am in the same situation. Is there a solution?
Jaco Verster
Jaco Verster 2017-7-6
I had a similar problem - found a great solution here: https://www.mathworks.com/matlabcentral/fileexchange/8998-surface-fitting-using-gridfit
Shivam Anand
Shivam Anand 2022-5-11
Ran in:
x=[32 20 67 1 98 34 57 65 24 82 47 55 8 51 13 14 18 30 37 39 10 33 21 26 38 81 83 60 95 22 17 5 72 46 99 52 12 25 96 29 70 85 43 69 19 78 97 31 89 53 2 91 48 71 61 15 36 84 94 50 11 80 6 7 49 74 9 88 40 79 27 68 73 64 63 59 86 23 35 58 45 28 100 42 93 87 16 90 41 66 54 92 77 4 62 76 75 56 3 44];
y=[96 75 24 9 83 49 27 77 3 23 17 31 40 13 7 52 51 21 98 47 64 79 78 91 44 16 15 100 84 99 63 68 70 30 54 76 97 73 33 5 88 8 71 66 62 25 60 42 72 45 18 11 28 59 89 65 10 55 69 81 12 26 20 95 87 41 74 50 93 22 43 90 14 34 82 35 56 38 80 32 1 57 6 36 37 61 29 58 2 48 4 46 67 53 92 86 94 19 39 85];
z=[55 31 11 45 83 36 86 49 15 57 42 46 8 94 88 47 54 81 98 41 32 35 56 85 9 89 37 60 23 62 67 100 78 76 73 80 10 20 68 34 77 93 1 63 53 12 22 99 91 40 84 24 33 3 43 19 92 97 6 82 64 25 26 79 95 4 44 58 5 21 70 29 65 87 96 90 51 14 18 2 72 28 71 39 52 7 27 59 50 61 48 30 66 69 17 13 74 16 75 38];
xlin = linspace(min(x), max(x), 100);
ylin = linspace(min(y), max(y), 100);
[X,Y] = meshgrid(xlin, ylin);
% Z = griddata(x,y,z,X,Y,'natural');
% Z = griddata(x,y,z,X,Y,'cubic');
Z = griddata(x,y,z,X,Y,'v4');
mesh(X,Y,Z)
axis tight; hold on
plot3(x,y,z,'.','MarkerSize',15)

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