vtkMatrix4x4::PointMultiply()

[David Gobbi]

Hi All,

Is there any need for the PointMultiply method?  I can't think of
any place where it should be used, and when I looked through the
rest of the VTK code I only found three places where it _was_ used,
incorrectly each time!

Both vtkRenderer and vtkViewRays use it, but they transpose the matrix
immediately beforehand so they should have been using MultiplyPoint
instead.

Also, vtkTransform::GetPoint() uses it if the PreMultiplyFlag is set -
this is (in my opinion) absolutely crazy and unexpected behaviour.
I know the rationale for having it work the way it does, i.e.
PreMultiply means c' = b'*A, PostMultiply means c = A*b, but in my
opinion GetPoint() should always use the latter for consistency
with MultiplyPoint(), MultiplyPoints(), etc.

I have eliminated the use of PointMultiply from my own code base and
will commit the changes tonight.  How would everyone feel if I 
removed PointMultiply from vtkMatrix4x4 altogether?

 - David

--
  David Gobbi, MSc                    dgobbi at irus.rri.on.ca
  Advanced Imaging Research Group
  Robarts Research Institute, University of Western Ontario