[vtkusers] vtkPlaneWidget and clipping

[John Biddiscombe]

> This is what I do not understand here.  I do not know to invert the 
> clipping function. I use "AddClippingPlane" on an instance of 
> vtkDataSetMapper:

Sorry, I assumed you were clipping a dataset with either
vtkClipPolyDat or vtkClipDataset
I see that you are using a hardware clipping plane in the mapper. In that case, you would need to invert the normal when you AddClippingPlane, but in this case, maybe you're right and flipping the arrow would be better...

see source code for vtkPlaneWidget and put in the reversal, I haven't looked at the code so don't know if there's a function already there to do it.

JB