[vtkusers] Rendering only a portion of an image

[James A Galbraith/GALBJA/CC01/INEEL/US]

I have some terrain data that I would like to change the scalar information
(i.e. color) on only a small portion of the image.  With the large number
of polygons (in strips) making up this thing, is there any way I can
restrict the rendering to only the region in which I changed the scalars so
it won't waste a whole lot of time rendering that which didn't change?

Thanks

James Galbraith
Idaho National Engineering and Environmental Laboratory
galbja at inel.gov