[vtkusers] Multiple vtkImageActors in the same render window but with different orientations.

[Maurice van de Rijzen]

Dear all,
I want to implement a 3D-image slicer (I'm aware of the existence of 
vtkImagePlaneWidget).
But I've a problem when I want to render two vtkImageActors in the same 
window.
I know how to extract two slices out of a 3D-cube using vtkImageReslice 
which gives me 2 2D-images.
In the next step I want to render both these slices in one render window

vtkImageActor ia
    ia SetInput [ySlice GetOutput]

vtkImageActor ia2
    ia SetInput [zSlice GetOutput]

vtkRenderer ren1
vtkRenderWindow renWin
    renWin AddRenderer ren1 
ren1 AddActor ia
ren1 AddActor ia2


Now my problem is thath the two slices are not orthogonally displayed.
I think I must change something at ia and ia2 but I cannot set something 
like a rotationmatrix.
Can someone explain me what I'm doing wrong

Maurice