How can I plot a 3D point and rotate it 180 degrees along one axis using the code I provided? I show reference image of what I want to achieve.

figure(1)
hold on
%grados de rotacion de cada eje
%solo en el eje y
for x=0:1:60
    y=x*2;
    z=0;
    pause(.001)
    o=[x,y,z];
    o=o*(pi/60);
    x=o(1);y=o(2);z=o(3);
    A=[cos(y),0,-sin(y);0 1,0;sin(y),0,cos(y)];%%Rotacion en Y
    B=[1,0,0;0,cos(x),sin(x);0,-sin(x),cos(x)];%%Rotacion en X
    C=[cos(z),sin(z),0;-sin(z),cos(z),0;0,0,1];%%Rotacion en Z
    U=A*B*C;
    %% 
    Ci=[5,5,0]';
    Cf=U*Ci;
    Q=[0,0,0;Cf';0,0,0;Ci'];
    hold on
    plot3(Q(:,1),Q(:,2),Q(:,3),'black')
    scatter3(Cf(1),Cf(2),Cf(3),'r')
    view(90,0)
    scatter3(Ci(1),Ci(2),Ci(3),100,'b','filled')
    plot3([0,10,0,-10,0,0,0,0,0,0,0,0],...
        [0,0,0,0,0,10,0,-10,0,0,0,0],[0,0,0,0,0,0,0,0,0,10,0,-10],'b')
    scatter3(10,0,0,'g')%%Eje X
    scatter3(0,10,0,'c')%%Eje Y
    scatter3(10,0,10,'m')%%Eje Z
end
scatter3(Cf(1),Cf(2),Cf(3),100,'b','filled')
for i=1:8
    text(Cf(1)+i,Cf(2),Cf(3),['P_{final}',num2str(i)],'VerticalAlignment','top')
    hold off
end

Ci=[5,5,0]';
pitch_calc = -asin(Cf(3)*Ci(2))

pitch_calc = 9.1849e-15

yaw_calc = asind((Cf(3)*Ci(1))/cosd(real(pitch_calc)))

yaw_calc = -5.2625e-13

roll_calc = asind((Cf(1)*Ci(2))/cosd(real(pitch_calc)))

roll_calc = 9.0000e+01 - 2.2412e+02i

Answer 1

[Rangesh]

Hello Martin,

I see that you're interested in rotating a 3D point along any axis. Here is the code that demonstrates how to achieve this:

figure(1)
hold on
%grados de rotacion de cada eje
%solo en el eje y
for x=0:5:180
    %% Changes made in the given code
    pause(.001)  
    Ci=[5,5,0]';
    R=rotx(x);
    Cf=R*Ci;
    %%   
    Q=[0,0,0;Cf';0,0,0;Ci'];   
    hold on  
    plot3(Q(:,1),Q(:,2),Q(:,3),'black')  
    scatter3(Cf(1),Cf(2),Cf(3),'r')  
    view(90,0)  
    scatter3(Ci(1),Ci(2),Ci(3),100,'b','filled')   
    plot3([0,10,0,-10,0,0,0,0,0,0,0,0],...        
    [0,0,0,0,0,10,0,-10,0,0,0,0],[0,0,0,0,0,0,0,0,0,10,0,-10],'b')    
    scatter3(10,0,0,'g')%%Eje X    
    scatter3(0,10,0,'c')%%Eje Y    
    scatter3(10,0,10,'m')%%Eje Z    
end
scatter3(Cf(1),Cf(2),Cf(3),100,'b','filled');
for i=1:8    
    text(Cf(1)+i,Cf(2),Cf(3),['P_{final}',num2str(i)],'VerticalAlignment','top');    
    hold off; 
end

• Here, I utilized the function "rotx" to generate a rotation matrix with a specified angle along the x-axis.
• "Cf" represents the position of the point "Ci" after applying the rotation matrix.
• Please note that I modified the loop to iterate based on degrees.
• If you wish to rotate along any other axis, you can utilize functions such as "roty" and "rotz".

You can refer to the following documentation and link to understand the rotation of points:

• https://www.mathworks.com/help/phased/ref/rotx.html
• https://www.eng.uc.edu/~beaucag/Classes/Properties/OptionalProjects/CoordinateTransformationCode/Rotate%20about%20an%20arbitrary%20axis%20(3%20dimensions).html#:~:text=Rotate%20space%20about%20the%20x%20axis%20so%20that,x%20axis%20and%20no%20additional%20rotation%20is%20necessary.

I hope this resolves your query.

Thanks,

Rangesh.