[vtkusers] vtkQuadricDecimation - color defects

[Nigel Mcfarlane]

I am using vtkQuadricDecimation to reduce a triangular mesh with color_scalar attributes.  After decimation, I get single-point errors in the colors which look as if they might be an overflow error in the color interpolation.  If the decimation is repeated recursively, the errors accumulate and start to form on the boundary points, turning the mesh edges black.  The errors appear when there is high-frequency noise in the color pattern; if the color is smooth there is no problem.  It does not seem to depend on the topography of the mesh.  The color scalars are unsigned char with 3 components.  AttributeErrorMetric is On, NormalsAttribute is Off, and the TargetReduction is 0.5.  I am using VTK5.10, but it also happens in VTK4.   Is this a known problem, and if so is there anything I can do about it? 
Thank you
Nigel McFarlane
University of Bedfordshire, UK
 
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