# 3D Polar Plot

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Paul Schütz on 27 May 2022
Edited: Torsten on 28 May 2022

Dear MathWorks comunity,
I want to plot a function containing two variables: r and phi.

sigma and a are constants, I want to display sigma x dependent of r and phi in an polar diagramm like the one shown below.

I really tried to find a soulution by myself (polarplot3d for example), but I couldnt find a way and my colleagues didnt knew either. It seems like an easy task for someone who knows what to do. I would be happy if someone could help me out.
best wishes
Paul from Germany

Torsten on 27 May 2022
Edited: Torsten on 27 May 2022
a = 1.0;
sigma = 2.0;
r = 0.2:0.001:3;
phi = 0:pi/100:2*pi;
[R,PHI] = meshgrid(r,phi);
X = R.*cos(PHI);
Y = R.*sin(PHI);
SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI));
contourf(X,Y,SIGMAx)
##### 2 CommentsShowHide 1 older comment
Torsten on 28 May 2022
I think I forgot a "sigma":
SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI)) - sigma;
SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI));

Bjorn Gustavsson on 27 May 2022
A quick search on the file exchange leads to these submissions:pcolor-in-polar-coordinates, 3d-polar-plot and polar-contour-plot. Most likely one of those will be (very close to) what you want, from there you should be able to modify to suit your need.
HTH
Paul Schütz on 28 May 2022
Thank you too :)

R2021a

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