How to generate a .stl file starting from a 3d figure

Hi everyone,

I'm dealing with the following problem:

I need to generate an .stl of the 3d figure that I have achieved with the following code (the one shown here below). I saw that a possible oprion is to use the function "surf2stl" however I'm unable to implement its inputs.

Does anyone know how to write the inputs of this function?

Any other suggestions are really appreciate.

Thanks for the attenction.

Vcub=[0 0 0; 1 0 0; 0 1 0; 0 0 1;1 1 1; 0 1 1; 1 0 1; 1 1 0];
%Vcub(:,2)=2*Vcub(:,2);
N=100;
seeds=1.5*rand(N,3)-0.25;

[Ver,Cel,C_tst]=voronoi3d_cuboid(seeds,Vcub);

figure
hold on
axis('equal')
view([-36 27]) 
for k = 1:length(Cel)
if ~isempty(Cel{k})
    col= rand(1,3);
    Vk = Ver(Cel{k},:);
    Fk = convhull(Vk);

    if exist('mergeCoplanarFaces.m','file')==2
        [Vk, Fk] = mergeCoplanarFaces(Vk, Fk);
        for i=1:length(Fk)
           patch('Vertices',Vk,'Faces',Fk{i},'FaceColor',col,'FaceAlpha',0,'LineWidth',3,'EdgeAlpha',1,'EdgeColor','k')
        end
         
    else
        trisurf(Fk,Vk(:,1),Vk(:,2),Vk(:,3),'FaceColor',col, ...
                'FaceAlpha', 1,'EdgeAlpha',1,'EdgeColor','k');
         
    end
end
end

xlabel('X');
ylabel('Y');
zlabel('Z');

[KSSV]

Read about stlwrite.

[Tonino Nucifora]

The error the software gives to me is the following:

Error using stlwrite (line 25)

Input argument must be a triangulation object.

Error in demo_voronoi3d_cuboid (line 42)

stlwrite('mytriangulation.stl',struct('faces',Fk, 'vertices',Vk));

What is wrong?

Thank you

Vcub=[0 0 0; 1 0 0; 0 1 0; 0 0 1;1 1 1; 0 1 1; 1 0 1; 1 1 0];

%Vcub(:,2)=2*Vcub(:,2);

N=100;

seeds=1.5*rand(N,3)-0.25;

[Ver,Cel,C_tst]=voronoi3d_cuboid(seeds,Vcub);

figure

hold on

axis('equal')

view([-36 27]) %3D

% scatter3(seeds(:,1),seeds(:,2),seeds(:,3),25, ...

% 'Marker','o','MarkerFaceColor',[1 0 0], 'MarkerEdgeColor','k');

% scatter3(Ver(:,1),Ver(:,2),Ver(:,3),25, ...

% 'Marker','o','MarkerFaceColor',[0 1 0], 'MarkerEdgeColor','r');

for k = 1:length(Cel)

if ~isempty(Cel{k})

col= rand(1,3);

Vk = Ver(Cel{k},:);

Fk = convhull(Vk);

if exist('mergeCoplanarFaces.m','file')==2

[Vk, Fk] = mergeCoplanarFaces(Vk, Fk);

for i=1:length(Fk)

h=patch('Vertices',Vk,'Faces',Fk{i},'FaceColor',col,'FaceAlpha',0.6,'LineWidth',3,'EdgeAlpha',1,'EdgeColor','k');

end

else

trisurf(Fk,Vk(:,1),Vk(:,2),Vk(:,3),'FaceColor',col, ...

'FaceAlpha', 0.5,'EdgeAlpha',1,'EdgeColor','k','LineWidth',5);

end

end

end

xlabel('X');

ylabel('Y');

zlabel('Z');

stlwrite('mytriangulation.stl',struct('faces',h.Fk, 'vertices',h.Vk));

Answer 1

[Arpit Bhatia]

Hi Tonino,

You need to download the stlwrite.m file from the following link: https://in.mathworks.com/matlabcentral/fileexchange/20922-stlwrite-write-ascii-or-binary-stl-files

(Please note that this file has not been created by or maintained by MathWorks)

With the stlwrite.m file in the same folder as the file with the above code, add the following command to the end of your code to generate the required stl file.

stlwrite('mytriangulation.stl',struct('faces', Fk, 'vertices',Vk)); 

The reason you were earlier facing the error “Input argument must be a triangulation object” is that you were calling the default MATLAB stlwrite function which requires a triangulation as an input argument. To use that function, you will need to first create a triangulation as specified below.

TO = triangulation(Fk,Vk(:,1),Vk(:,2),Vk(:,3));
trisurf(TO,'FaceColor',col, ...
        'FaceAlpha', 1,'EdgeAlpha',1,'EdgeColor','k');
stlwrite(TO,'test.stl')

[Tonino Nucifora]

Thanks for the reply.

The code, however, allows to generate only one polyhedron in STL, but I cannot pass the whole structure.

[Arpit Bhatia]

Since the polygons are being generated inside a loop, Vk and Fk only contain the vertices and faces of the last polygon generated. To create the STL for the entire structure, please store the vertices and faces for the entire structure and then pass them to stlwrite.

[Abdelmadjid Boualleg]

Hi Arpit Bhatia

Thank you for your help above regarding the provided information about Stlwrite for Voronoi 3D, but when I used that function, it gives me Stl file with triangulation edges, not Voronoi edges as you can see in the attached picture, therefore I kindly ask you to help me for getting the Stl of Voronoi not triangulation. Thank you very much in advance.

[Akshay Kumar Pakala]

Hey Arpita Bhatia

I would like to know if the stlwrite function works to create the entire voronoi cuboid if i store the Vk and Fk matrices at every loop into 2 seperate cells or in two different multi-dimensional dimensional matrix respectively?

Thank you