Converting MATLAB code to AutoCAD

I am new to MATLAB. I have been trying to convert the code to excel, so I can convert that into autocad, but nothing seems to be working. It is possible to do because I need it for school and past students have done it. This is my code:

t = linspace(0, 2*pi, 201);  % this is used to create 201 evenly spaced 
% points between 0 and 2pi.
r = sqrt(abs(7*sin(5*t)));    % 7 controls the size of the shape. 
% 5 controls the amount of petals on each
% side.
% abs is used to ignore all imaginary
% values.
% sin and sqrt are used to give a lower
% value.
[x, y] = pol2cart(t, r);      % this command transforms corresponding elements of 
% the polar coordinate arrays of theta and ro to 2-D 
% cartesian coordinates.
z = 3 * (x.^2 + y.^2);         % The (x.^2 + y.^2) is used to control how curved 
% up the flower is. The (3) controls the size of
% the flower.
% Plotting the 3D surface
figure(1);   % this is used to create a new figure window
fill3(x, y, z, 'c');          % this is used to plot on a 3-D axis. 
% the c is used to fill the shape with a cyan color.
grid on;                       % this is used to show gridlines on the plot.
% Creating a triangulation object
tri = delaunay(x(:), y(:));   % Triangulate the surface
% Save as an STL file
vertices = [x(:), y(:), z(:)];         % Create vertices matrix
stlwrite(tri,'flower.stl'); % Save as an STL file using triangulation objectt = linspace(0, 2*pi, 201);  % this is used to create 201 evenly spaced 
% points between 0 and 2pi.
r = sqrt(abs(7*sin(5*t)));    % 7 controls the size of the shape. 
% 5 controls the amount of petals on each
% side.
% abs is used to ignore all imaginary
% values.
% sin and sqrt are used to give a lower
% value.
[x, y] = pol2cart(t, r);      % this command transforms corresponding elements of 
% the polar coordinate arrays of theta and ro to 2-D 
% cartesian coordinates.
z = 3 * (x.^2 + y.^2);         % The (x.^2 + y.^2) is used to control how curved 
% up the flower is. The (3) controls the size of
% the flower.
% Plotting the 3D surface
figure(1);   % this is used to create a new figure window
fill3(x, y, z, 'c');          % this is used to plot on a 3-D axis. 
% the c is used to fill the shape with a cyan color.
grid on;                       % this is used to show gridlines on the plot.

i have since then produced the following code, but when I try to open it with excel, an error comes up.

t = linspace(0, 2*pi, 201);  % 201 evenly spaced points between 0 and 2pi
r = sqrt(abs(7*sin(5*t)));    % Polar coordinates
[x, y] = pol2cart(t, r);      % Convert polar to Cartesian coordinates
z = 3 * (x.^2 + y.^2);        % Calculate z coordinates
data = [x(:), y(:), z(:)];    % Create a matrix where each row is [x, y, z]
filename = 'flower_data.xlsx'; % Define the filename
writematrix(data, filename);   % Write data to Excel

the error is:

excel cannot open the file 'flower_data.xlsx' because the file format or file extension is not valid. verify that the file has not been corrupted and that the file extension matches the format of the file

can anyone please help?

[Les Beckham]

I assume that the error is shown by Excel when you try to open the file, not when you run the above code. Correct?

What version of Excel do you have? Could it be old enough that it doesn't support the .xlsx format (only the old .xls format)?

[Pat Gipper]

When I ran your code it produced the Excel file that opened just fine on my computer. I attached the file here. Can you open it?

Also the longer code on top produced an error on line 25 because tri was not a triangulation object.

[Josianne]

@Pat Gipper I opened it. Thank you so much! Do you also happen to know how I can convert the excel file to autoCAD to have it show the same figure in MATLAB? I need to 3D print it.

[Pat Gipper]

I can't help you on Autocad questions, and suggest they are best posed on the Autodesk community website.