How do I create a sphere without sphere function that will inflate like a balloon utilizing the getframe function?

I have a basic code set for movement of a string that I would like to follow suit with a sphere inflating from an arbitrary initial radius (R_0) to an end radius (R_F):

clear String u x
c = 1.0; % wave equation constant
k = 0.5; % maximum initial string deflection
L = 1.0; % length of string
N = 3; % number of Fourier sine terms
M = 501; % number of movie frames, each corresponding to a specific time
TT = 5.0; % total time
x = [0.000:0.01:1.00]';
hold off
for T = 1:1:M
    t = (T - 1) * (TT / (M - 1));
    u = zeros(size(x));
    for n = 1:1:N
        lambdan = c * n * pi / L;
        bn = (8 * k / (n^2 * pi^2)) * sin(n * pi / 2);
        u = u + bn * cos(lambdan * t) * sin(n * pi * x / L);
    end
    plot(x,u,'LineWidth',6,'Color','green')
    xlim([0.0 1.0])
    ylim([-0.5 0.5])
    String(:,T) = getframe;
end
movie(String,1,60)

How can I set this coding above to suit my purposes for a sphere? Again, not utilzing the Sphere function that exists in matlab.

Thank you

Answer 1

[darova]

Use surf to create a 3D surface

rr = linspace(0,0.5,20);
tt = linspace(0,2*pi,40);
[R,T] = meshgrid(rr,tt);
[X,Y] = pol2cart(T,R);

for 
    % ...
    z = interp1(x-0.5,u,rr);
    [Z,~] = meshgrid(z,tt);
    surf(X,Y,Z)
    pause(0.05)
end

[Zjuv9021]

Hmm I'm not quite following based on the line of code I displayed.

I'd like to know how to first: draw a sphere based on a mathematical equation and then correspondingly plot it utilizing the above getframe and movie functions:

for T = 1:1:M
    t = (T - 1) * (TT / (M - 1));
    u = zeros(size(x));
    for n = 1:1:N
        lambdan = c * n * pi / L;
        bn = (8 * k / (n^2 * pi^2)) * sin(n * pi / 2);
        u = u + bn * cos(lambdan * t) * sin(n * pi * x / L);
    end
    plot(x,u,'LineWidth',6,'Color','green')
    xlim([0.0 1.0])
    ylim([-0.5 0.5])
    String(:,T) = getframe;
end
movie(String,1,60)

I'm not sure on how I can set it up to plot a sphere to start with.

Thank you

[darova]

You want to plot a sphere or plot your curve in 3D (surface)?

[Zjuv9021]

I essentially would like to obtain a visualization of a sphere inflating in 3D space.

[darova]

Can you make a simple drawing or something? How it should looks like?