[vtkusers] determine axis of rotation?

[Marty Humperdink]

I have a 4x4 linear transformation matrix that
describes translations and rotations in one frame of
reference. I know that this transformation is a single
rotation about a line not coincident to any of the
axes of the first coordinate system. Can anyone
suggest a technique to find this line using the 4x4
matrix that I have? In other words, I have the matrix
describing the rotation about an arbitrary line and I
need to find find that line.

I've been playing with a few methods and an
eigenvector apporach seems obvious but I'm having
trouble putting it together. I would be most
appreciative if someone could suggest a way to do this
using VTK.

Thanks
MH

 

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com