How do I create a time-lapse video of a 3D plot?

I have a recording of the trajectory of the two feet of a person, given as two time series of 3D coordinates. (two matrices of Nx3, with N being the number of samples). The feet are modeled as points in 3D space. I want to create a video that shows the movement of the feet over time.

What would be the best way of doing this in MATLAB?

Answer 1

[Kevin Holly]

One way is to run a similar code as shown below in Live Editor. It will automatically create a video from the for loop that you can export.

matrix = rand(10,3);
matrix2 = rand(10,3);

ii=1;
foot1 = scatter3(matrix(ii,1),matrix(ii,2),matrix(ii,3),'filled','r');
hold on
foot2 = scatter3(matrix2(ii,1),matrix2(ii,2),matrix2(ii,3),'filled','g');
xlim([0 1])
ylim([0 1])
zlim([0 1])

for ii = 2:size(matrix,1)
    foot1.XData = matrix(ii,1);
    foot1.YData = matrix(ii,2);
    foot1.ZData = matrix(ii,3);
    foot2.XData = matrix2(ii,1);
    foot2.YData = matrix2(ii,2);
    foot2.ZData = matrix2(ii,3);
    drawnow
end

Or you can use writeVideo and getframe function

v = VideoWriter('NameYourVideo.avi');
v.FrameRate = 1;
open(v);

for ii = 2:size(matrix,1)
    foot1.XData = matrix(ii,1);
    foot1.YData = matrix(ii,2);
    foot1.ZData = matrix(ii,3);
    foot2.XData = matrix2(ii,1);
    foot2.YData = matrix2(ii,2);
    foot2.ZData = matrix2(ii,3);
    drawnow
    frame = getframe(gca); %Note if you use gca (get current axis), make sure it doesn't change size - x, y, and z limits were defined above in this example to prevent this.
    writeVideo(v,frame);
end
close(v)

[Etay Kalifa]

Thank you so much! that did the trick

[Kevin Holly]

If it worked, I would appreciate it if you would accept the answer.

[Etay Kalifa]

would you happen to know how I could add a time stamp to the video based on the sample rate?