[vtkusers] Principal Axis

[Anwar Upal]

Kiran:

In addition, there also is C++ code available from
 
http://www.magic-software.com/Numerics.html

which computes the principal axis by solving for the eigen vectors and eigen 
values.  If you want to do this then download 

MgcEigen.h MgcEigen.cpp MgcRTLib.h MgcMath.h MgcMath.cpp MgcMatrix3.cpp 
MgcMatrix3.h MgcVector3.cpp MgcVector3.h

As you can tell, it is a lot more complicated than what Lisa has suggested.  But 
it is another option.

peace,
:) anwar


Date: Fri, 13 Jul 2001 17:15:02 -0400
To: "Kiran, P (CORP, GEITC)" <P.Kiran at geind.ge.com>,
vtkusers at public.kitware.com
From: "Lisa S. Avila" <lisa.avila at kitware.com>
Subject: Re: [vtkusers] principal axes
ge.com>

Hello Kiran,

vtkOBBTree has a method which essentially does this:

   // Description:
   // Compute an OBB from the list of points given. Return the corner point
   // and the three axes defining the orientation of the OBB. Also return
   // a sorted list of relative "sizes" of axes for comparison purposes.
   void ComputeOBB(vtkPoints *pts, float corner[3], float max[3],
                   float mid[3], float min[3], float size[3]);


Lisa


At 05:38 AM 7/9/2001, Kiran, P (CORP, GEITC) wrote:

>Hi all,
>
>Has any one come across, some methods of finding principal axes for a set of
>3-D points?
>Are there any available classes in vtk to do this kind of stuff.
>
>Pl. send me some suggestions on how to do this.
>
>Thanks in advance for help.
>
>-Kiran
>
>__