Plot cylinder symmetry axis

I am using the function cylinder to generate a cylinder model. I would like to show the cylinder axis in my plot.

There is a function to rapidly plot the axis or i have to necessary build it and than plot ?

[Raj Gopal Mishra]

We can Also plot it with simple Circle patch repeating it for number of times till we get height.

theta=linspace(0,pi,100);

r=1.5; % radius

h=10; %height

x=r*cos(theta);

y=r*sin(theta);

z=zeros(size(x));

while z(1,1)<h,

patch([x -x], [y -y], [z z], 'r')

hold on

z=z+0.1;

end

hold off

view(3)

Answer 1

[Star Strider]

I am not certain what you intend by ‘axis’.

If you just want a line through the axis of the cylinder, try this:

[X,Y,Z] = cylinder;

figure
surf(X, Y, Z)
hold on
plot3([0 0], [0 0], [-1 2], ':r', 'LineWidth',2)
hold off
grid on

Experiment to get the result you want.

[gaetano mallardo]

Thank you for your answer, it was exactly what i was looking for, even if i realised there are more cylinder function. Anyway starting from your code i arrived to a solution.

What i was using it's:

 model = cylinderModel(params)

Basing on your code i developed the same solution for my model class and i post it here in case it can help someone in future:

figure()
hold on
plot(model)
hold on
cilindro = model; % just name change
plot3([cilindro.Parameters(1,1) cilindro.Parameters(1,4)], ....
    [cilindro.Parameters(1,2) cilindro.Parameters(1,5)], ...
    [cilindro.Parameters(1,3) cilindro.Parameters(1,6)],...
    ':r', 'LineWidth',2)

[Star Strider]

As always, my pleasure.

For reference, the cylinderModel class (link) is part of the Computer Vision System Toolbox (link) that I do not have.

I added that and MATLAB to the ‘Products’ tags.