CODEWITHSUNDEEP
matlabvolumesurface
Enchanted_Eggs
Enchanted_Eggs

Reputation: 63

MATLAB - Plotting a smooth volume from 3D scatter plot data

So I have data in the form [x y z intensity] that I plot on a scatter3 figure with xyz axes. The colour of the data is used to dictate the intensity value. Problem is, using a scatter plot means the data points show up as discrete points. What I need, is a smooth shape - so I guess I need some kind of interpolation between the points?

I've tried using trisurf, but the problem with this one is that it interpolates between points that it shouldn't. So where I should have 'gaps' in my surface, it joins up the edges instead so it fills in the gaps. See the attached pics for clarification.

Does anyone have any suggestions?

The code I use is as below (the commented out scatter3 is what does the scatter plot, the rest does the trisurf):

% Read in data
dataM = csvread('3dDispersion.csv');

% scatter3(dataM(:,1), dataM(:,2), dataM(:,3), 5, dataM(:,4),'filled');

% Plot
hold on;
x = dataM(:,1);
y = dataM(:,2);
freq = dataM(:,3);
tri = delaunay(x,y);
h = trisurf(tri, x, y, freq);

% Make it pretty
% view(-45,30);
view(3);
axis vis3d;
lighting phong;
shading interp;

The scatter plot

The trisurf plot

Upvotes: 2

Views: 3499

Answers (1)

Adam Ryason
Adam Ryason

Reputation: 588

Use the boundary function in Matlab. This will apply a mesh similar to shrinkwrap over your points. In order to reduce the "gap closers", you will want to increase the "shrink factor".

Try K = boundary(X,Y,Z,0.9)

Where X, Y & Z are the vectors of your data points

https://www.mathworks.com/help/matlab/ref/boundary.html

You can then use trimesh or related surface plotting functions depending on how you want to display it.

Upvotes: 1

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