how to draw a hyperboloid?

Hai,

I need to draw a hyperboloid in matlab. How is it I could do it?

BSD

[Fangjun Jiang]

If you run membrane, is the figure that comes out close to what you want?

[bsd]

what is membrane?

[Fangjun Jiang]

Run membrane in Command Window to see.

[bsd]

no, it not a hyperboloid.

[Fangjun Jiang]

Then you need to explain what is hyperboloid and what you want to do. I can search for hyperboloid and it gives me lots of hits. For your benefit, barely mention hyperboloid in your question is not sufficient, right?

[bsd]

hyperboloid is a three dimensional representation of a hyperbola. Just like sphere, as sphere is a three dimensional and circle is two dimensional.

BSD

Answer 1

[UJJWAL]

Hi BSD,

I hope the following code will help. Reply back :-

clc;
clear all;
[X,Y,Z] = meshgrid(-10:0.5:10,-10:0.5:10,-10:0.5:10);
a=1;
b=1;
c=1;
V = X.^2/a^2 + Y.^2/b^2 - Z.^2/c^2;
p=patch(isosurface(X,Y,Z,V,1)); % This is the key step. It involves getting the part of the volume corresponding to the surface defined by the equation
set(p,'FaceColor','red','EdgeColor','none');
daspect([1 1 1])
view(3);
camlight

Hope This helps..

Happy To Help

UJJWAL

[bsd]

It gives both the upper and lower portion. But I need only the upper portion of the hyperboloid. How to do that? Looking for your reply.

BSD

[UJJWAL]

Hi BSD,

That is very easy as you just have to change the range of the x,y and z points you use in meshgrid

For getting the upper portion you just need to set z from 0:0.5:10

so in the above code just replace the meshgrid line with the following :-

[X,Y,Z] = meshgrid(-10:0.5:10,-10:0.5:10,0:0.5:10);

Hope This Helps

HAPPY TO HELP

UJJWAL

Answer 2

[HAGOS EMAN]

Thanking you all! Very helpful!

Answer 3

[Fangjun Jiang]

As long as you have the mathematical equation describing that hyperboloid, you should be able to generate some data and then draw it.

Take a unit sphere for example, the equation is x^2+y^2+z^2=1; If you carefully set the mesh grid for x and y, then you can calculate the corresponding value for z. Then you can use surf() to plot it.

MATLAB has the sphere() function. Here I am using it to generate the data first and then plot it. Running sphere alone can plot it too.

[x,y,z]=sphere;
surf(x,y,z)

Answer 4

[Chaowei Chen]

[x,y]=meshgrid(-10:10);

r_sq=x.^2+y.^2;

z=sqrt(r_sq+1);

surf(x,y,z)

[Bud Kelly]

This is very clever. Thank you, I will keep it for reference. I had thought that you needed to purchase Symbolic Math Toolbox to plot 3D explicit functions, but now I am encouraged. Thanks.

[Benjamin Backus]

That doesn't look like an ellipsoid to me. The 3rd line should rather be:

z=sqrt(200 - r_sq);

in order to have an ellipsoid of equation x^2 + y^2 + z^2 = 200 (200 because x and y have magnitude 10)