I have a set of points and I need to rotate them of a certain angle. How can I do?

I have a set of points with specific coordinates and I need to rotate them of a certain angle. This means that I have to:

• translate all nodes so that the center becomes (0,0,0)
• rotate ? degrees around z(?) by multiplying the coordinates with a rotation matrix
• translate coordinates back to the original position

How can I do?

Answer 1

[Mann Baidi]

Hi,

I understand you would like to translate the coordinates in xyz axes so that the centre '(0,0,0)'. You can try subtracting the original coordinates with their 'centroid'. Here's is an example code:

% Define the original set of 3D coordinates (XYZ)
original_points = [1, 2, 3; 4, 5, 6; 7, 8, 9];

% Calculate the centroid of the points
centroid = mean(original_points);

% Translate the points to center them at the origin
translated_points = original_points - centroid;

% Display the original and translated points
disp('Original Points:');

Original Points:

disp(original_points);

     1     2     3
     4     5     6
     7     8     9

disp('Translated Points:');

Translated Points:

disp(translated_points);

    -3    -3    -3
     0     0     0
     3     3     3

% Plot the points for visualization
figure;
scatter3(original_points(:, 1), original_points(:, 2), original_points(:, 3), 'o', 'DisplayName', 'Original Points');
hold on;
scatter3(translated_points(:, 1), translated_points(:, 2), translated_points(:, 3), 'x', 'DisplayName', 'Translated Points');
xlabel('X');
ylabel('Y');
zlabel('Z');
legend('Location', 'best');
grid on;
title('Translation to Center');