How to convert 3D plot to .STL

I wonder how to export an implicit 3D function to a .STL file for 3D printing.

I have searched for some tools like

https://kr.mathworks.com/matlabcentral/fileexchange/4512-surf2stl

https://kr.mathworks.com/matlabcentral/fileexchange/68794-make-stl-of-3d-array-optimal-for-3d-printing

but cannot figure out how to do it. The following code is the 3D plot that I want to convert to .STL. Thank you in advance.

h=fimplicit3(@kidney2);
    set(h, 'EdgeColor', 'none', 'MeshDensity', 125);
    
view(-110,80)
axis([-0.1, 0.1, -0.1, 0.1, 0, 0.5])

function out=kidney2(x,y,z)
   kidney1=@(x,y,z) (x.^2+y.^2).^(2)-(x.^3+y.^3).*(z/4-z.^2).^(1/2);
   
   dt=0.25*(z/4-z.^2).^(1/2);
   
   out=kidney1(x+dt,y+dt,z);                
end

Answer 1

[Raghava S N]

Hello,

A possible solution is to download the “stlwrite.m” file from the following link: https://www.mathworks.com/matlabcentral/fileexchange/20922-stlwrite-write-ascii-or-binary-stl-files

This is prescribed by a MathWorks staff member in the following MATLAB Answer - https://www.mathworks.com/matlabcentral/answers/623773-how-to-generate-a-stl-file-starting-from-a-3d-figure#:~:text=You%20need%20to%20download%20the%20stlwrite.m%20file%20from%20the%20following%20link%3A.You can refer to the same MATLAB Answer, where they also describe some intricacies of “stlwrite”.

[Dyuman Joshi]

These solutions won't work because there is no data available corresponding to implicit surface generated.