[vtkusers] removing points from a vtk render window

[Kevin Wright]

>I have the following question, I set my rendering pipeline and it renders 
>the data correctly now I need to remove some of the data points and render 
>the data again. The call is done in a callback function after the setup 
>stage was finished.

If you're changing a pointset object directly after the initial render, 
you'll have to call Modified() after the changes to indicate to the 
pipeline that an update is required at the next render.

Kevin.