[vtkusers] Picking points in a volume

[Will Schroeder]

Hi Robb-

At 12:16 PM 3/18/2003 -0700, Robb Brown wrote:

>I've tried vtkPointPicker but it always returns a point on the surface of 
>the bounding box of the uncropped volume.  I can get the pick position 
>using vtkPropPicker.GetPickPosition() but what space are these coordinates 
>in?  The documentation says they're global coordinates (world?) but if I 
>rotate the volume and click on the same point I get different z values.
>
>Anybody know how to do this?


I would suggest that you use vtkPointWidget in combination with a probe 
filter to get the scalar value in the volume. It is not clear what it means 
to pick a point in a volume rendering. The point widget shows an x-y-z 
cursor and clearly indicates where the pick is occurring.

Will