Error while concatenating two .stl files

I'm trying to combine my two .stl files into one and keep getting this error message "Dimensions of arrays being concatenated are not constant wheras I used virtually the same code for both solids as you can see:

Code 1:

% Clear all previous commands
clear all
close all
clc

figure(2)

% Variables you can change
Sizex = 1; %average length of RVE
Sizey = 1;
Sizez = 1;
Def = 60; %definition

% Variables you shouldn´t change
SFactx = (Sizex/2)/pi; %size factor of RVE
SFacty = (Sizey/2)/pi;
SFactz = (Sizez/2)/pi;

A = SFactx*pi; %lowest and max coordinates of meshgrid
B = SFacty*pi;
C = SFactz*pi;


Dx = A/Def;%definition factor
Dy = B/Def;
Dz = C/Def;

% Generation of gyroids
[X,Y,Z] = meshgrid(-A:Dx:A, -B:Dy:B, -C:Dz:C); %creates mesh grid


    % Gyroid equation
    OBJ =(cos(X/SFactx).* sin(Y/SFacty) + cos(Y/SFacty).* sin(Z/SFactz)...
        + cos(Z/SFactz).* sin(X/SFactx)+(0));
     T = 0.5;
    OBJ =(OBJ-T);
   


   
    % Isosurface and isocap
    [F1,V1] = isosurface(X,Y,Z,OBJ,0);
    [F2,V2] = isocaps(X,Y,Z,OBJ,0,'below');
   

    %Combines isosurface and isocaps into one
    F3 = [F1;F2+length(V1(:,1))];
    V3 = [V1;V2];
   



    % Visualization
    P = patch('Vertices',V3,'Faces',F3,'FaceColor', ...
    'cyan','EdgeColor','none');
   
    view(3)
    camlight

   
    %Visualization
axis equal
stlwrite('G1-T05.stl',V3,F3)

Code 2:
% Clear all previous commands
clear all
close all
clc

figure(1)

% Variables you can change
Sizex = 1; %average length of RVE
Sizey = 1;
Sizez = 1;
Def = 60; %definition

% Variables you shouldn´t change
SFactx = (Sizex/2)/pi; %size factor of RVE
SFacty = (Sizey/2)/pi;
SFactz = (Sizez/2)/pi;

A = SFactx*pi; %lowest and max coordinates of meshgrid
B = SFacty*pi;
C = SFactz*pi;


Dx = A/Def;%definition factor
Dy = B/Def;
Dz = C/Def;

% Generation of gyroids
[X,Y,Z] = meshgrid(-A:Dx:A, -B:Dy:B, -C:Dz:C); %creates mesh grid


    % Gyroid equation
    OBJ =(A*B*C)-(cos(X/SFactx).* sin(Y/SFacty) + cos(Y/SFacty).* sin(Z/SFactz)...
        + cos(Z/SFactz).* sin(X/SFactx)+(0));
     T = 0.5;
    OBJ =(OBJ-T);


   


   
    % Isosurface and isocap
    [F1,V1] = isosurface(X,Y,Z,OBJ,0);
    [F2,V2] = isocaps(X,Y,Z,OBJ,0,'below');
   

    %Combines isosurface and isocaps into one
    F3 = [F1;F2+length(V1(:,1))];
    V3 = [V1;V2];
   



    % Visualization
    P = patch('Vertices',V3,'Faces',F3,'FaceColor', ...
    'magenta','EdgeColor','none');
    view(3)
    
    camlight

   
    %Visualization
axis equal
stlwrite('G1-T06.stl',V3,F3)

%How do I solve this problem?
Thanks

Answer 1

[Varun]

Hello!

I tried to run the code on my end and after removing the “clear” statements from Code 2, the code ran perfectly! I am assuming that you used “stlwrite” from this File Exchange: https://www.mathworks.com/matlabcentral/fileexchange/20922-stlwrite-write-ascii-or-binary-stl-files . The output I obtained was:

To concatenate the two .stl files generated, you may make use of Microsoft’s 3D Builder or other similar applications. Hope this helps!

[Lovett]

Thank you so much

Answer 2

[DGM]

To combine STL files, triangulation objects, or sets of F,V data, see this example:

https://www.mathworks.com/matlabcentral/answers/2131056-combine-two-stl-into-one#answer_1568109

FWIW, it's not necessary to use FEX #20922 in modern versions. You already have an STL encoder stlwrite, and #20922 will cause a name conflict unless you rename it. They're not the same function, and they don't behave the same.