Esophagus 3D Modelling Issue

Hello,

I am trying to build a 3D model of the esophagus (approximated to a cylinder), and I need to define the radius layer-by-layer. I have the data concerning the radius of every cross-section at some instants in time, but I do not know how can I create a dynamic 3D model. I took a look at the function cylinder and patch, but I did not manage to come up with anything.

Any help would be greatly appreciated.

[Sara]

What do you need? To define the points on the surface? To plot it nicely? What is your goal?

[Vittorio]

I would like to have a nice view of the 3D cylinder built using different radii for the layers composing it.

[Sara]

Try this and let us know what you think. the radius and its position x are invented, replace them with your data.

clc
clearvars
close all
radius = [1 1.1 1.2 1.3 1.4 1.5 1.4 1.4 1.1 0.8];
x = linspace(1,30,10);

n = 600;
xx = zeros(numel(x),n);
yy = zeros(numel(x),n);
for i = 1:numel(x)
    [xx(i,:),yy(i,:)] = circle(x(i),0,radius(i),n);
end
surf(repmat(x',1,n),xx,yy)

function [xx,yy] = circle(x,y,r,n)
ang=linspace(0,2*pi,n);
xp=r*cos(ang);
yp=r*sin(ang);
xx = x+xp;
yy = y+yp;

[Image Analyst]

sara, post as an official Answer so you can get credit for it.

[Vittorio]

Thanks for your answer! This is what I was looking for. Can you please tell me how can I rotate the cylinder to have it displayed vertically?

[Ben11]

To interactively rotate the cylinder type "rotate3d on" after your call to surf.

doc rotate3d

[Vittorio]

Yes, I saw the button there to rotate it, but I would prefer the code to do it from the start, without doing it manually.

[Sara]

Look into

rotate

[Vittorio]

I managed to rotate it, thanks for the tip. Still, I need my structure to be symmetric, not shifted with respect to the various radii. What I have now is this:

[Vittorio]

I searched on file exchange and I found this amazing .m file:

http://www.mathworks.com/matlabcentral/fileexchange/21758-cylinder-surface-connecting-2-points/content/cylinder2P.m

Thanks to all for the support and your answers!