[vtkusers] [Fwd: Selecting points on image slices]

[Joël Schaerer]

== It seems my message did not get posted to the list. I'm posting it
again ==

> Hello all,
> 
> I am trying to put together a basic interface to select points in an
> image volume.
> The volume is displayed using vtkImageActor, one slice at a time. The
> slice plane is normal to the z axis.
> To find the coordinates of the point on the image, I use a picker. The
> problem is, no matter what picker I use (vtkWorldPointPicker,
> vtkPointPicker), the z coordinate is always wrong. vtkPointPicker always
> returns the z of the base slice no matter what slice I am displaying.
> vtkWorldPointPicker returns a somewhat random z, depending on image zoom
> and camera orientation.
> 
> Am I on the right track? Is there a better solution to this problem? Is
> this a bug?
> 
> many thanks,
> 
> joel