How do I make a 3D plot with assigned values?

Hi all,

I am trying to plot a 3D mesh grid based on the x, y and z coordinates and an assigned value. Each coordinate has its own value, and thus I would like to plot the values assigned to that coordinate. My code is the following:

Svalues=readmatrix('s_values.csv');
xs=Svalues(:,1);
ys=Svalues(:,2);
zs=Svalues(:,3);
s=Svalues(:,4);
figure; 

points=length(xs);
for n=1:points
    scatter3(xs(n),ys(n),zs(n),s(n));
    hold on
end

It is probably varily easy, but I do not seem to get it right. Can anybody help me out?

Furthermore, the coordinates are symmetrical in 3D, and I would also like to plot that into a matrix (or so), so that I can multiply it with other matrices. Any tips on how to do that? Thanks in advance!

Answer 1

[Walter Roberson]

Svalues = readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/856420/s_values.csv')

Svalues = 216×4

0 0 0 1.6100 0 0 1.0000 0.2760 0 0 2.0000 0.0226 0 0 3.0000 0.0013 0 0 4.0000 0.0000 0 0 5.0000 0.0000 0 1.0000 0 0.2760 0 1.0000 1.0000 0.0976 0 1.0000 2.0000 0.0128 0 1.0000 3.0000 0.0008

xs=Svalues(:,1);
ys=Svalues(:,2);
zs=Svalues(:,3);
s=Svalues(:,4);

N = 100;
xmin = min(xs); xmax = max(xs);
ymin = min(ys); ymax = max(ys);
zmin = min(zs); zmax = max(zs);
[XQ, YQ, ZQ] = meshgrid(linspace(xmin, xmax, N), linspace(ymin, ymax, N), linspace(zmin, zmax, N));
F = scatteredInterpolant(xs, ys, zs, s);
SQ = F(XQ, YQ, ZQ);
Levels = linspace(min(SQ(:)), max(SQ(:)), 12);
for L = Levels
   isosurface(XQ, YQ, ZQ, SQ, L);
end

[Lieke Pullen]

Hi Walter, thank you, this is what I am looking for! I was wondering, can I also make duplicate this so that it becomes a sphere?

[Walter Roberson]

Svalues = readmatrix('https://www.mathworks.com/matlabcentral/answers/uploaded_files/856420/s_values.csv');

xs = Svalues(:,1);
ys = Svalues(:,2);
zs = Svalues(:,3);
s = Svalues(:,4);

N = 100;
xmin = min(xs); xmax = max(xs);
ymin = min(ys); ymax = max(ys);
zmin = min(zs); zmax = max(zs);
[XQ, YQ, ZQ] = meshgrid(linspace(xmin, xmax, N), linspace(ymin, ymax, N), linspace(zmin, zmax, N));
F = scatteredInterpolant(xs, ys, zs, s);
SQ = F(XQ, YQ, ZQ);
Levels = linspace(min(SQ(:)), max(SQ(:)), 12);
Levels = Levels(2:end-1);

M = [
     -1 -1 -1;
     -1 -1  1;
     -1  1 -1;
     -1  1  1;
      1 -1 -1;
      1 -1  1;
      1  1 -1;
      1  1  1;
     ];

for L = Levels
    for K = 1 : size(M,1)
       isosurface(XQ*M(K,1), YQ*M(K,2), ZQ*M(K,3), SQ, L);
    end
end
set(findobj(gca, 'type', 'patch'), 'FaceAlpha', 0.3);

[Lieke Pullen]

Thank you very much! This is what I was looking for.