How to have a plot3 vector and sphere on same figure?

Hello all, I'm currently trying to write a program where I'm drawing a line within a sphere, and it changes size based on the dataset. The line will always start at the origin, but I want the line to dynamically change based on the endpoint given, which will be given by a dataset. The problem I'm running into is that I can't get this line to be on the same figure as the sphere, even with hold on. when it did work previously, it just traced a path and left it there, which obscured the motion of the vector throughout the space. I've posted the code below, and any help would be appreciated.

figure(1) %creating animation window

sphere % creating sphere for visualization

alpha('clear') % making sphere clear for visualization

hold on; % make it so that all animations are drawn on same figure

for k=1:1200 %looping through data set

    v = z(k); % z coordinate

    vec1 = [0,0,0];

    vec2 = [0,0,v];

    vec = [vec2;vec1];

    figure(1);

    h = plot3(vec(:,1),vec(:,2),vec(:,3), 'LineWidth', 2, 'Color', 'r');%updating the line animation data set

    clf(h, 'reset');

    refreshdata;

    drawnow;

end

Answer 1

[Ryan Takatsuka]

Try something like this:

figure(1) %creating animation window

sphere % creating sphere for visualization

alpha('clear') % making sphere clear for visualization

hold on; % make it so that all animations are drawn on same figure

t = linspace(0,1,1200);
z = cos(4*pi*t);

for k=1:1200 %looping through data set
    % Get each of the plotted components
    children = get(gca, 'children');
  
    % If there is only one, this is the first iteration, so do nothing.  Otherwise, remove the line
    if length(children)>1
        delete(children(1));
    end
  
    v = z(k); % z coordinate
    vec1 = [0,0,0];
    vec2 = [0,0,v];
    vec = [vec2;vec1];
    figure(1);
    h = plot3(vec(:,1),vec(:,2),vec(:,3), 'LineWidth', 2, 'Color', 'r');%updating the line animation data set
  
    % This needs to be here
    pause(.001)

end

[Maxwell DeVoe]

Thank you so much! I understand what you have done, but I just had a question about z. Why does it have to be set to cos(4*pi)? Forgive me if it's obvious, my math is a bit rusty.

[Ryan Takatsuka]

Oh I just randomly set that function to describe the z variable because you didn't include values for z in your initial code posted here.

Answer 2

[Maxwell DeVoe]

Oh ok, so it doesn't use the values I have in my z data field?

[Ryan Takatsuka]

No, but it should work with any vector of z values (You might have to change the indexing of the for-loop to loop over z depending on the length of the vector).

[Maxwell DeVoe]

Sweet, it works with my data now. Thank you Ryan, you were a big help.