[vtkusers] Disable "zoom" and "translate"

[curator]

Dear list,

Basically I have a vtkRenderer, a vtkRenderWindow and and 
vtkRenderWindowInteractor. Everything is connected correctly and I can 
draw my scene and rotate with leftmouse, zoom with rightmouse and 
mousewheel. Clicking the wheel + motion translates the scene. 
Furthermore, much is possivle by a touch pad, but I am not exactly sure 
what this event is.

The question is: Is there any simple method to disable zooming and 
translating? I would like to look always at the center (0,0,0) from a 
constant distance, but from different directions. Is there a simple way 
to do so?

kind regards,
curator