How do I create a cylindrical surface mesh with a changing Z coordinate?

t = linspace(0,4)

th = t*.25*pi

z = linspace(0,50);

[TH,Z] = meshgrid(th, z)

R = 30-16*sin(th)

[X,Y,Z] = pol2cart(TH,R,Z);

mesh(X,Y,Z);

daspect([1 1 1])

I'm trying to create a visual for a project, where an object's path is graphed on the x-y plane, with a mesh that extends upwards to represent it's velocity on the z-axis. The object's position is described in polar coordinates. I've managed to graph the path and a mesh of a constant height, but nothing seems to work when I try to parameterize Z with respect to t. Does anyone have any ideas?

Answer 1

[Voss]

Maybe something like this:

t = linspace(0,4);
th = t*.25*pi;

v = 20+20*(sin(2*t)+1); % speed (i.e., magnitude of velocity)

z = linspace(0,max(v));
[TH,Z] = meshgrid(th, z);
Z(Z > v) = NaN;

R = 30-16*sin(th);
[X,Y] = pol2cart(TH,R);

mesh(X,Y,Z);
daspect([1 1 1])