Date: Jul 14, 2013 6:29 AM
Author: Alon Rozen
Subject: Drawing ellipsoid
Hi all,

I have an ellipsoid which is represented by a center - [x0 y0 z0]

and a symmetrical 3x3 matrix - A.

I know that using the Matlab function:

[Eig_Vec, Eig_Val] = eig(A)

I will get the size of the ellipsoid axes on the diagonal of Eig_Val and the direction of the axes in the columns of Eig_Vec (respectively).

In order to plot the ellipsoid I use the commands:

[X,Y,Z] =ellipsoid(x0,y0,z0,Eig_1,Eig_2,Eig_3);

surf(X,Y,Z);

Were Eig_1,Eig_2,Eig_3 are on the diagonal of Eiv_Val.

This will create an ellipsoid which is parallel to the axes.

My problem is - how do I use the eigenvectors information to rotate the ellipsoid so it will represents the original one?

I know I have to use the Matlab command 'rotate' but I couldn't figure out how exactly.

Any help will be much appreciated.

Alon