[vtkusers] Is the Oriented Bounded Box unique?

[Anwar Upal]

I know that OBB computes the eigenvectors and eigenvalues of 3D data but I 
do not know exactly what that implies...  For example, for a set of 3D 
points, does the OBB compute a unique bounding box (is it compute a minimum 
volume or a minimum dimension box)?  Or is there many possibilities and it 
picks one out of many?  How does it keep track of the orientation?

Any ideas would be appreciated.

Thanks,
AU