[vtkusers] black polygons

[Louis Desjardins]

Hello..

I am rendering an image that uses vtkPlaneSource, vtkCutter, vtkLODActor

The image is animated, and is a set of QuadCells that are color coded, and 
the colors change at a rate of about 15 Hz

However, I keep getting these wierd looking black polygons that dont seem to 
get updated with the rest of the colors,

I can send you a screendump if you are curious to see what I am talking 
about

But can anyone think of any reason why this might be occuring?
Thank you
LD