Filling with colour the space inside object

Hello, how can I fill my following object with colour inside?

Answer 1

[Star Strider]

Perhaps you can adapt the solution in: fill area between two polar curves to your problem.

[Anh Phan Viet]

Thank you very much but I've only succeeded in filling the colour with 2D, but failed with 3D. Could you please give me a hint?

My code in 2D: patch([X1 X_arc1 fliplr(X2)], [Y1 Y_arc1 fliplr(Y2)],'g');

patch([X3 X_arc2 fliplr(X4)], [Y3 Y_arc2 fliplr(Y4)],'g');

My code in 3D: patch([X_1 X_arc1_new fliplr(X_2)], [Y_1 Y_arc1_new fliplr(Y_2)], [Z_1 Z_arc1_new fliplr(Z_2)], 'g');

patch([X_3 X_arc2_new fliplr(X_4)], [Y_3 Y_arc2_new fliplr(Y_4)], [Z_3 Z_arc2_new fliplr(Z_4)], 'g');

[Star Strider]

Add figure(3) to your code:

surffcn = @(x,y,H) surf([x;x],[y;y],[zeros(size(x)); ones(size(x))*H]);     % Plots Surfaces

H = 0.5;                                                                    % Height Of Sides

figure(3)
surffcn(X1,Y1,H)
hold on
surffcn(X2,Y2,H)
surffcn(X_arc1, Y_arc1,H)
surffcn(X3,Y3,H)
surffcn(X4,Y4,H)
surffcn(X5,Y5,H)
surffcn(X_arc2, Y_arc2,H)

patch([X1 X_arc1 fliplr(X2)], [Y1 Y_arc1 fliplr(Y2)],[ones(1,size(X1,2)*3)*H],'g');
patch([X3 X_arc2 fliplr(X4)], [Y3 Y_arc2 fliplr(Y4)],[ones(1,size(X3,2)*3)*H],'g'); 
hold off
axis('equal')

producing:

Note that you can make the height of the sides whatever you want by changing the ‘H’ value.

This only colours the upper surface. If you want to colour the lower surface as well, duplicate the two patch calls, and replace ‘H’ with 0 in only those two additional patch calls.

[Anh Phan Viet]

Thank you very much, now I want to convert it to file .stl but I don't know how. Could you please help me?

[Star Strider]

I have no idea how to convert it to a STL file, or even what a STL file is.

That was not part of your Question.

If it had been, I would have not have posted my Answer.

If my Answer in any way helped you solve your problem, please Accept it!

[Anh Phan Viet]

I am so sorry, I really appreciate you and your answer. Anyway, thank you so much for helping me

[Star Strider]

As always, my pleasure!